Hi bianz
I'm afraid I can only comment on my own experience with Cam2life and Dlink. So can't make a comparison with the rest.
For mobile broadband, if you mean using it on your iphone, it should work, even a low speed plan. I use a 1M service I get free from Starhub, and it works fine. But if you are trying to use mobile broadband as your home connection (where your cameras are), then I think it's not advisable. I suggest you get a fixed line service for reliability (though I got it to work on mine). If you already have the mobile one, you can always give it a try first. As for the unlimited plan, I assume you are talking about the mobile plan. An unlimited plan would be nice, but I seriously doubt you would use up alot of data. I believe a 12G plan from most mobile providers would be more than enough.
As for routers, I believe any broadband router will work since the cam2life is really plug and play. Have not encountered any problems with routers I used (and I've used at least 3 brands in the last couple of years).
Hope this helps.