XB1 i'm sure has had to pay sony a small fortune to use BlueRay in they're device no doubt, so i'm sure that bumped up the price a bit. Sony for the PS3 also used a 1 off designed 8 core Cell Broadband processor and of course the BR player that they developed, bumping up the price to £425. BR now is cheap (for sony) and they're using "off the shelf" parts to make the PS4 which should bring down the cost for them to hopefully about £300.
As for MS selling more 360's than Sony did PS3's, that's true, but they had 1 year head start, it's been out 8? years compared to PS3's 7? The figures arent far off either, 77 million 360's to 70 million PS3's, thats only 10% more yet they were on sale for 14% longer...
I've no idea what i'm going to do this year, no idea which, if any I will buy. Don't like the large grip controller of the 360, but that's probably because i've been using a PS controller for about 15 years. I guess the price may come into it, but probably more importantly the games. XB1 has 1 month exclusivity on CoD games and the have Forza which looks great, but PS4 will have GT6 and I have a £1k racing rig which uses a T500rs steering wheel which I'm almost certain won't work with the XB1. So I guess if any, it'll be the PS4, but only if GT6 comes out for it rather than the PS3 which is believed it'll be released on.