I have a few questions the Vista as it seems to currently be a decently priced well featured unit. However from a cyclist perpective I don't think I have seen the following answered with enough clarity for my brain at least.
Does it interfere with HRM say a Polar?
If you get the autoroute maps can you disable certain streets one by one? Around the big D it isn't just highways and interstates we'd want to avoid.
Can you get stuff from mapmyride or bikely onto the vista? I think bikely export .GPX

My wife and I usually go for a sunday ride and she rides before work during the week. Having turn by turn directions nearly failed us again this sunday when we found 6 miles of our route was pretty much closed to bicycle because of construction. Maps (of the 4-5 counties we ride in) would make a good backup but I'd really like a GPS like we have in the car when we do travel.