It think it a little unfair to call the KK obsolete, but IMO it is probable the KK will become less and less supported. This is the case with the DX and the DX owners are annoyed.
Re: the Kobo, I played with one the other day. Nice looking unit, slick, black rubberized feel. However, it was slow to respond. And no buttons, ick. Hate that.
Re: the T1. Also played with one. Nice device, really nice. The browser was really nice. And yes, I have a Sony, so I'm likely to have Sony fan-boy tendencies though I try to resist. They also had a 350 in the sony store for 75$ though it was pink
Wouldn't bother me.