Westcoast is right, your loyalty will take a hit if you jump and you'd need some time to get it back up anyway.
Since you'll be at either school for probably two years, which will give you the best situation to make deep NT runs? Also, if the other DII team has a lot of seniors, be careful - you may make a good run this season but then find yourself rebuilding in Y2. And any school you apply to will weight the most recent season heaviest.
I'd recommend considering something other than just a sprint to DI as fast as possible. Its easier to adjust to DI if you take a little more time moving up and are able to get something better than the D/D- schools. Also it can take less time to get to high DI schools if you take an extra season at DII and get a better DI job to begin with rather than rebuilding some backwater program for a few years just to get to C- prestige.