So I bought a Yamaha P-90 and have had it one week. I still don't know enough so say how it compares to the other makes and models out there, but for my uses (so far) it seems to fit the bill.
(play at night, portable, runs on 12VDC, not TOO heavy & most important feels like a piano).
I purchased it with a stand (cheap double-X brace jobee), a pair of headphones (reasonably comfortable - Sony), and a cheap folding bench. FWIW I purchased it at a Guitar Center and they reduced the price $100 on the piano, so it worked out! I still need to get a bag.
I've used it at least an hour a day for the past week. It is really nice to be able to play at night. I actually hauled it to work the last two days so I could practice at lunch because my evenings were booked. If you ever decide to carry your piano in to work, be forwarned, you get some strange looks, some interesting comments ("most people carry a briefcase, but I've never seen ...), a LOT of questions and not much practice the first time! But, you quickly learn who else plays! They just - show up!
I just finished playing on my acoustic which I still prefer, but the P-90 is kinda "fun" and I can "bang away" if I want - no guilt or funny looks from the family, it's great!
So never mind make/model - just get a digital! Better yet - get 2 - one for home and one to practice a work ;-)