Here's where I stand;
I got the Xbox and it was great for a while, then support for it just stopped when the 360 came out, fair enough, not entirely a major issue for me but was still a bit miffed.
Then the 360 was also great at the start, I really enjoyed it. It had wonderful games that could not be found elsewhere at the time. Great dashboard and a nice community online at the time, I still remember playing Lost Planet online when it came out and everyone was so polite, was bizzare xD
But then after a while it just fell apart, the exclusives just stopped? Well no, that's a lie, it still has a fair few exclusives but it shy's in comparison to other consoles. I still have my 360 for the Gears series though, I do have a soft spot for that
But Microsoft just seemed to change direction of where they were headed to me, more about home entertainment in centralized location which is great, but they seem to of forgotten about people who purely like to play games or mainly want to. Also a note about the home entertainment thing, I just do not get why I have to be a gold subscriber to access services like netflix? Something I have already paid for and can access anywhere else without needing an extra...
I guess the thing that puts me off the Xbox brand the most is Microsoft's business decisions and that makes me cautious about the next Xbox. I will have to wait until much later in its life cycle to make a choice about it. Also the rumours of it having a bigger focus on Kinect will put me off, six-axis (which is hardly used anyway) and waving the wii-mote is as much as I like? I agree that the Kinect is a great piece of kit, but I'm just personally not interested in it at all. I like having a controller with physical feedback. No doubt it will still have a controller though of course, but I guess we'll wait till E3.
I've had the PS1, 2 and 3. Have I been disappointed with either of them at any stage? Nope. The PS1 is still actually my favourite console and probably will never change due to it being part of my childhood after playing the megadrive, but I'm confident that they'll still consider my needs as a gamer. Granted the social stuff did make me raise an eyebrow but they still had the games to show and I'm quite interested in them.
And of course I do think exclusives are important, I don't see the point in owning console A if all of it's games or a great deal of them are also on console B while console B also has a ton of games not on console A, let alone the fact that the multi-plat games are also on PC, which is what I'll most likely get them for. You could argue that most of your friends have games on console A and to be honest in that scenario that's fair enough, IF you want to invest financially into that to play with them. Despite that, most of my friends left Xbox and went Playstation and PC so it doesn't really concern me.
I'll still wait till E3 of course before I make any final decisions, but based on past experiences I'm pretty confident I'll know what I want to get and possibly even expect. But lets hope there are some surprises in store.
Would I say I have a brand loyalty? Maybe, although I've not bought any of the PSP's and actually chose the 3DS over the Vita. And I am considering a Wii U but I'd like to see more games on it that I'd consider buying and maybe a price cut before I do. But if I did have brand loyalty, I'd say it's due to how I have been treated as a customer by the respective companies? I always kept an open mind when approaching the decision of buying a console or product, but I also take into account my past experiences as previously mentioned.
Never did buy the saturn 
was too expensive.