Upvote:5
Last time I was there, it was very easy to go from one side to the other (that's not the case in Geneva for example) and I can't imagine it has become more difficult recently, with Schengen and everything. So you can choose the side that's more convenient for you.
Things to be mindful of:
Incidentally, the exchange rate will be unattractive but you could probably also rent a Swiss car and be charged in euros if you wish.