I bought a 2720 years ago and it still works like a champ. Ran it on the bike until last fall when I got a Zumo and Montana, now the 2720 is on fulltime Jeep duty. I cannot comment on the other units being suggested, but the 2720 is good. If it has never been registered with Garmin, you might be able to get a single free map update out of it.
Eventual Master of the Obvious
2005 R1200GS | 2013 R1200GSW | SOHC4 208 | DoD 2032 | BMWMOA | BMWRA | YB