The system is new and haves lot of downside. Number 1: the cost is a bit too much. For a tourist some might think it's a bike rental for the day but it's actually a tool for you to go to place A to B. Otherwise some extra charge for the additional hours can get expensive.
Number 2: The Vandalism: if you lock your bike in and it shows that you actually locked it correctly. You should have a ticket complying that you're no longer responsable for the bike itself; some guy got charged some damage he didnt do which currently has no escalation or way to escalate it. By having a ticket, the system should be able to make a overall check-up and basically have some 24/7 camera looking at bike.
Number 3: One of the major issue is mostly the fact that you need a credit card. Why a prepaid card wouldn't be an option? It"s ridiculous.
Number 4: too many Bixi are used in some really particular place causing some penury of bixi to some place: some staff x-fering bixi should be working on that a lot more efficiently.
Overall: pratically, environnementaly friendly and suited to the already existing bike culture in Montreal!