Of the new carriers, only WIND seems to be taking prominent retail space in the malls and shopping streets and competing for Bell and Roger's typical customer base. The other carriers I find are opening storefronts in areas that nobody would have considered (i.e. Church & Dundas, etc.) and aren't putting much into them. Very cheap operations and obviously targetting a completely different type of customer.
Moblicity is massively advertising, especially on the TTC. I've seen a couple of their stores in my wandering around downtown. But it's true, it seems like Wind is the biggest right now - but they were the first ones on the scene. Also, Public Mobile and Moblicity both seem to be targetting recent immigrants by locating in lower-class neighbourhoods and having long distance deals with unlimited calling to various countries.
My main reason for not getting a Wind phone is that they still use billing. I am a huge fan of prepaid, I don't want any surprises come the end of the month and would far rather run out of minutes than run up a bill. I like that Public Mobile and Moblicity both use unlimited plans and don't have monthly billing. That's one of the main problems I've had with existing companies - their prepaid plans are often a huge rip-off and filled with sneaky loopholes to discourage people from choosing that option. It makes sense - they want you to run up a huge bill because they make more money when you're not consciously thinking of how much money you have left in your account.
So I take it no one out there is using public or moblicity?