If you visited Head-Fi I should mention that people there tend to fall into the "flavor of the month" spell quite easily. The Senn has an established good reputation - plus it will most likely provide you with better isolation than the AKGs. Sound quality is up for debate, but for the typical noisy BART commute, I'd go for isolation over sound quality (within reason, of course).

Oops, just read your last sentence. Trying both out might work, too.