You may want to try out a bunch of different ones, they all feel and behave differently.
I didn't like the no-pedal types, for instance, and I didn't like the pedal-assist type where the assist kicks in too fast- but that's just me. I'm very happy with my Gazelle for it's upright seating, its smooth assist (it's smooth even without assist!), its baggage carrier, and its waterproofness - it's made for the Dutch, after all. Definitely buy a chain that fits into the built-in lock.