MAtransplants

Thanks. Right now there's about $40 difference on Amazon for the 550/550T, so it's right at that point where it's not clear .... ah well.

Thanks. I guess what I was asking (but didn't specifically ask) was whether there was anything that could *only* be stored in the on-board storage, and therefore adding an external SD card wouldn't help. I thought I had read something somewhere about the way the 100K topos were stored internally on the oregons was special for the "T" series (maybe reduced number of segments?), and that led me to question whether there was anything special about the on-board storage. Sounds like that's probably not the case, but just wanted to double-check. The cost difference isn't much....

Currently looking at "T" vs. "non-T" Oregons as well. If you assume you don't care much about the built-in 100K maps themselves, is there any advantage to buying the "T" for more on-board storage vs. just buying an SD-card for more external storage? Seems like that would make sense, as it appears that the 100K topos aren't great and I'll likely replace them anyway with 24K (either Garmin or free), plus probably the birds-eye data as well. Is there any concern about total storage capacity? What is typical for regional US Topo Map sizes? Is the SD card capacity more than I'd ever need, making that basically a non issue? Plus, I can always buy the 100K topo from Garmin later if I decide I want it for whatever reason, right? Just want to make sure there isn't some non-obvious reason why the extra on-board storage for the "T" version will be something I'll regret not getting later... Thanks!