Both are decent systems and cameras, but the usual advise is go to a decent store and handle the camera. One might be better than the other, but handle badly (for you).

as for the pros and cons with Sony and Pentax, i'll pass on that as i'm a Canon user. Though one common plus point (for some) is inbody image stabilisation, which makes all lenses IS. With my Canon I have to buy IS lenses, however that's not a big concern for me.

As for the accessories like filters, batteries, bags and memory cards you'll get them cheaper on the web. Though sometimes the deals in the shop make a bundle look appealing (e.g free bag worth Ł90 - when it really isn't).