I have had a Garmin 296 since April and have been very impressed indeed. The battery life was important for me, as I do not have a cigar lighter, and it is excellent, especially when you turn the backlighting down a tad. It will happily go on for up to 10 hours, which is rather longer than the aircraft or my bladder !
Updating is so easy as well on the Garmin website, and not expensive at $35. We also have a Skymap IIIC panel mounted in the aircraft, which was there when I bought it. I tried to get used to it and failed. The refresh rate is slow and I just did not find it easy, having got used to the 296. Data updates are very expensive, around £100, and involve having to send off for a new card, so no on line updates possible.
The 296 comes with a yoke mount, charger etc and it simply does exactly what it says on the tin.
Lysander