I got my Ifinder largely because of a good price ($150) - on a model that had been sitting on their shelf for a while. In fact after getting it I realized that its firmware was several iterations out of date, and I haven't been able to get the update to work. However for my purposes it does work.
It's internal memory is good (something like 10 tracks of 2000 pts each), plus they can be written to the SD card, allowing me to record two weeks worth of driving without any problem.
I haven't had a chance to compare its reception under trees with other brands, but I get the impression from comparing reviews that it does as well as the others.
It does have a connector for an external antenna, however it uses an unpowered one, so I can't just adapt a common Garvin one - I either have to buy the Lowrance one or make my own.
Fortunately the 12v power adapter wasn't too expensive, so I can use it full time in the car without worry about batteries.
The base map for the Ifinder includes federal and state highways, but only a scattering of lesser roads. I could, for extra bucks, download much more detailed maps from their mapping software package. The particular submodel that I got also came with a 32mb database (on SD card) of places and points of interest, giving me yet another way of finding the nearest Motel 6
I might add that I prefer getting my current direction of travel from the GPS than from a digital compass.
paulj