Personally, I'm not convinced with Android on a mobile phone - yes it can make very good multi-purpose devices, and I'm quite happy with it for them and things like tablets, but all the phones I've sampled, have not actually been very good at being actual phones (ie that side of the functionality hasn't been either good, well thought out, or worked well in practice).
For iPhones, I think they generally tend to be reasonably feature rich and a good all-round balance. Now-and-again, there's the odd weakness where they do get the occasional thing wrong, which tends to either get bluff-or-blustered or hand-waved about. Yes, sure, I think there's more people get drawn to their products based on trends, memes and attitudes than function - but then function over form isn't for everyone. Personally, I avoid Apple consumer devices, not because I'm a hater, per se, but because I don't like some of the restrictive decisions they often make, the way in which you largely have to use them (iTunes) and cost seems high, largely based on perceived desirability.
For a while I did like Nokia's Symbian OS, but they went astray with it, really. Often very good hardware - I still find my N8 an excellent handset, and am perfectly happy with my N8 running Symbian Anna. I have another N8 running Belle, and although I don't hate the improved look and feel, and swishyness, they've dumbed down, removed, or neutered a lot of the things I find truly useful on my Anna handset. Symbian dying out was probably something of a inevitability - and truth be told, I'm rather ambivalent, really - whilst I am happy with it in some respects, I don't know as it had any true advantage - the bigger pull was that in some examples, it was run on some very nicely spec'd handsets by Nokia. As to them moving to Windows mobile, I'm somewhat ambivalent - I've only really played briefly with their handsets, having setup a couple for relatives.
BlackBerries have always seemed very purposeful, and most seem to be able to get the communicatiion thing done with them well - be it actual conversation, or various kinds of messaging. I have a PlayBook as well as a couple of Android tablets, and have to say, the OS on the PlayBook is truly superb, simple, yet efficient to use, snappy, easy to control what's running, as opposed to, say, Android having it assume it can do all that for you. Sure there are some gaps in app support, but the OS on the PlayBook is superb - truly - and it's party piece of true multi-tasking, is rather cool. The gestures and easy dealing with opening, moving between, and closing apps is very slick, and given I've probably spent more time using Android on a tablet that the BB PlayBook OS, I have to say, it's only taken me a very brief period to prefer the way the PlayBook operates (and it is quite reminiscent of WebOS).
I've only briefly played with a Z10, but BB10 is an evolution of the PlayBook's OS (ie QNX, just that BB10 has taken that a little further), so I'd be completely happy with how it works, how you use it and how you can control it (that hasn't changed as I understand it).
Personally, I think I may go for a BlackBerry handset at contract renewal point - especially if a BB10 handset comes within my budget. I'm not convinced with any of the other major players, and if nothing else, the forerunner, in terms of OS, to BB10, is, by itself, worthy of admiration, so I'll probably go for a BlackBerry of some point - because any will likely work well with my PlayBook, and a BB10 one would be great, as BB10 is coming to the PlayBook at some point.
That's not to say I'd recommend that's what others should do - I always think there's far too much advocacy in the gadget market, and not enough people truly have a bit of an experiment themselves, and find what fits their wants / needs the most. And not that I buy into it, myself, but I think the often perceived default of an iPhone isn't necessarily a bad one, for most - although I'm not convinced that so many opting for them does truly align with what they really probably should be (by that I mean what they really can best afford) spending on such tech.
