The Good: it plugs into the obdII and uploads a new map. It comes with a few maps on it for increased performance, fuel economy, valet (no RPMs above 3500) and no start. You can only upload one map at a time, but all others are saved on the device and can be uploaded fairly quickly.
It also has data logging capabilities, some live data reading, trouble code reading and clearing and some performance measuring (0-60, 60ft, sample dyno reading)
The bad: it is no longer supported by Cobb Tuning since 2010. So the only way to get a custom or updated tune (that I know of) is to go to an Accessport authorized tuner, pay for tuning time and have them save the tune on your device. I'm not even 100% sure they can upload a new map onto your device but believe so. Since there is no support from Cobb I do not believe you can find updated maps from other users or have web downloads of maps from Cobb any longer (besides the last map they created in 2010). I may be a bit wrong on this since I haven't researched what user web communities are available with updated maps, but know that Cobb hasn't put out updated maps on anything for Accessport that doesn't come factory turboed since 2010.
more info from Cobb here:
http://blogs.cobbtuning.com/2010/07/...consolidation/
Not a bad deal for people like me who live an hour away from a Cobb Tuning location, but maybe not the best option if you don't have an Accessport tuner you trust close by.