Can you only keep 1 game at a time or an you download as many as you like as long as you're within the daily download limit?
I'm on the 2mb connection atm so 350mb per day is just unacceptable. I mean most of the new titles takes up 4Gb+ each!
Besides I've already played most of these games before so it's not worth it for me.
VM doesn't have a 350MB cap, it has a 350MB throttle limit. If you exceed that limit between 4pm and 12am, you will be throttled down to 1mbps (i.e. your maximum speed will be halved) for 4 hours. When that 4 hours is up, your speed goes back to normal and your data counter reset.
So assuming you manage to max out your connection, you'll be able to get the first 350MB in just over 23 minutes. In the next 4 hours you'll be able to pull down 1800MB. Then 350MB in 23 minutes, 1800MB in the next 4 hours, etc. So you'd be able to get your 4Gb in under 9 hours if you leave it going and you get full speed (and assuming you started at 4pm).
Having said that, one of the FAQs says that they attempt to package the game in such a way that the engine and early levels are downloaded first, so you can start playing before it's finished downloading.
Looks like you can download as many as you like and play them when and where you like (even on different PCs, though you can't have two people logged into the same account at the same time). They just stop working if you end your subscription.
Note also that they do a 'download to own' service too. Probably no cheaper than buying from the store though.