Hi Greywolf,
I'm in Minnesota and like you I hate to see the riding season end. Just put mine in storage yesterday. Our local HD dealer has a nice new heated building specifically for winter storage. Washes the bike going in and coming out in the spring. Keeps the battery on a tender all winter. $200 total. I think that's reasonable. Lots of folks here keep their bike in cold storage. Pull the battery and throw on a bike cover. The only guy I've ever seen using the bubble had his in his basement Rec room. It seemed to work ok but it looked kind of flimsy. He since has ditched the bubble and keeps in the garage.
Not really answering your question except to say that it was me I don't think I'd waste the money but I'm old school.
If you do get one let us know how it works out.
Best,
Blues