Six different winners from four different teams suggests that the DW12 has indeed leveled the playing field. But what have been the strengths and weaknesses of the teams and drivers? Here's the half-term report, by RACER editor David Malsher.
(Written in order of each team's leading driver in the championship.)

TEAM PENSKE
4 wins
There's no question that The Captain's three-man squad is the strongest of the Chevrolet-powered teams more often than not. Winning the opening four rounds of the season proved that, with Helio Castroneves taking his first non-oval win for two years, and Will Power overcoming grid penalties in both Barber and Long Beach and following that up with a controlling performance in Brazil.
Ryan Briscoe, who should have started from pole at Long Beach (grid penalty), went on to take pole at Indy and was strong at times in the race; Power was the strongest opposition to Honda-powered cars in Detroit (in qualifying and race), he was a potential winner at Texas until he received a (deserved) drive-through penalty, and Castroneves has been what he wasn't this time last year – consistent enough deserve his top-five position in the championship.
But Honda-powered cars' superior fuel economy at Indy and slightly higher speed down the straight at Detroit means that this championship fight is a long way from being over. Had Scott Dixon not accounted for himself in Texas and then had IndyCar do it for him in Milwaukee, he'd be right in Power's wheeltracks.

Briscoe has had a very up-and-down year – two poles and a decent run to third at Texas, but other days he's barely noticeable. Castroneves continues to defy the laws of aging, and occasionally pulls out a special performance. But it's hard to watch a guy who produces a decisive win at St. Petersburg and a podium finish at Barber then cause a cluster down at Long Beach's final turn or spin into a wall at Detroit.
Power remains the man to beat on road and street courses, and no one can deny he's doing the best with what he's got – over half a second quicker than his nearest teammate in qualifying at both Detroit and Brazil. But he squandered a brilliant performance at Texas Motor Speedway, and his superlative Sao Paulo victory must seem a long time ago. Going for championships by accruing points is anathema to this guy; he's always looking to deliver the knockout punch. That being the case, it's time for Power, Penske and Chevrolet to head to Victory Lane once more.
ANDRETTI AUTOSPORT
1 win
Like most drivers, Ryan Hunter-Reay can look back on a couple of incidents in the first eight races and then examine ruefully the 41-point gap between himself and the championship lead. The DNFs at Texas and Indy weren't his fault; the penalty at Long Beach was. But the win at Milwaukee last weekend has deservedly sent his confidence sky-high, and there's no reason why he shouldn't be a top-five contender at each of the remaining races. And consistency goes a long way in IndyCar in 2012.
For proof, he can just look across the garage to teammate James Hinchcliffe, who's yet to finish higher than third place, but lies second in the championship, just 31 points behind Power. Apart from the DNF at Detroit where track debris launched him into the tire barrier, the retina-scalding green car has been one you can count on to reach the checkered flag and in a top-six position.
That's not to suggest Hinch has been in cruise-and-collect mode, though. As his teammates will tell you, he's very fast in qualifying as well as on race day and on all types of circuit. His front row starts at Barber Motorsports Park and Indy were the result of great laps and the fact that we expect to see him near the front at all races says a lot for last year's Rookie of the Year.
Marco Andretti has had a nightmare year so far. When he's fast, it's not usually in a session that counts, and minuscule errors – more than ever, it seems – cost you big when you're trying to get to the last round of qualifying, the Firestone Fast Six. He was the strongest Chevy runner at Indy on race day, but the car's handling went south and its tire usage turned ferocious. The accident, when it came, was not surprising; he was simply trying to make up for lost time and wayward handling.
Andretti and engineer Allen McDonald have no time to lose to get their season back on track. Iowa this weekend could see the start of a revival; Marco is the defending race winner and Andretti Autosport always find a strong setup there, if not for qualifying then at least for the race. But the events that follow will be more telling as to whether Marco is destined to always start behind his teammates this year. He has the talent to match them but he seems to have lost the key to unlock it.
CHIP GANASSI RACING
2 wins
So Chip Ganassi's leading driver in the championship has slipped to third, but – no offense meant to either Hinchcliffe or Andretti Autosport – I'd be surprised if that were still the case in three or four races' time. (AA is on its way back; it's not there at Penske/Ganassi level just yet.)
Dixon still has days of bad luck (Long Beach DNF, unfortunate strategy/yellow-flag at Brazil and error by Race Control at Milwaukee – although none of them cost him a win) and his own error in Texas will haunt him for a while. But, like Power, he quickly found speed in the DW12, which at one time he was worried wouldn't suit his style, and the confident way Dixon dealt with anyone and anything at Detroit suggests that there'll be more days in the future when he's the man to beat. There's no reason to think he won't be taking the title battle down to the wire.
And – one of my most frequent mantras – never count out Dario Franchitti. He had a couple of anonymous races earlier in the year, but in Brazil he qualified on the front row. And since then, despite having a disaster in Texas and a DNF in Milwaukee, he has cut his deficit to championship leader Power from 98 points to 69. Franchitti's fine win at the biggest race on the planet and a perfect drive through the field to second at Detroit prove he should now be fine on all types of circuit. The two Canadian races, rather than Iowa, should prove whether he's finally found a setup that suits his driving style. If he has, he's a title contender.
Graham Rahal currently lingers outside the top 10, but we're about to hit a sequence of tracks that should enable him to leap up the championship table and recapture the form that only bad luck prevented from scoring a handful of podiums at the back end of 2011.
Clipping the wall on the penultimate lap at Texas a couple weeks ago will still be a fresh wound, but let's not forget how well he ran all night – and kept that oversteery Ganassi setup under him longer even than Dixon. Then also recall that only restraint and good track ethics kept him from muscling past Castroneves for a podium finish at Barber and, while the television director failed to notice his passing skills at Detroit, a lot of his rivals did. A two-lap delay in the pits before the restart was a cruel fate.
Charlie Kimball, as in his rookie year, has had some good race day performances – at Long Beach, Sao Paulo, the Indy 500 and Detroit – but reproducing that form race after race will never be possible while he qualifies in the back half of the grid. There's just too much danger of getting caught up in other people's accidents or the field getting away from you in the early stages. For now he's a fine rep for Novo Nordisk but he needs to show Chip he can be a consistently fine driver.