I'm using an Airmap 600C. Flown about 10 000nm with it so far, according to the odometer
I chose it over garmin for size, price, regular AA batteries instead of battery packs, and the memory is easily expandable with off-the-shelf sd/mmc cards, as opposed to garmin's expensive memory packs. The display can be fully customized and is as easy to use as any of garmin's x96 units.
Not sure where you are R22Driver, but I purchased mine from Calgary Pilot Supply, and it included a 4 disk Canadian topographical database; which is amazing. The detail is no different than having a topo map right in front of you. With the 512mb card (included) there's enough room for me to store topo data of my 'backyard' alongside the jeppson database.
On the downside, the plastic screen is soft and can scratch easily. I just stuck a pda protector on it and cut to fit. The colour screen is hard to see without the backlight on, so I can get about 8 hrs out of a fully-charged pair of NiMh batteries with the backlight on all the time.
All card programming must be done through their proprietary sd/mmc card reader (included). You can only register/program up to 4 cards per unit. The jeppson database cannot be copy/pasted onto a larger card, so if you go to a larger card, you lose the aviation data. I wonder if lowrance will install this data onto a larger card for you?
I haven't ran off of aircraft power yet, but it does look inconvenient. The voltage regulator is in the cigarette adapter, so you cannot wire it direct to a canon plug; rather, you must purchase a female cig adapter and run that into your canon plug. The cable plugs into the bottom of the unit (as opposed to the back, with garmins), and it is rather large for a simple dc power supply, so this may interfere with where you suction-cup it to the panel.
Good luck with your purchase.