I would really recommend the 2000 over the 1. I have both sizes, both yamaha, and frankly while the 1kw is nice, it has a hard time running many house appliances, it works a treat for the boat though. The 2kw does a much better job running standard house loads.
As an example, during our hurricane this year I had the 1kw (my brother has the 2). It was almost enough power to start a small window unit, but I wound up having to soft start the compressor by disconnecting the fan while the AC spun up. The 1 would also only run one appliance at a time (maybe some cfl lights
On the 2kw I can start the window unit easily, and it can run either the TV or the fridge at the same time. The extra power really is handy.
As far as reliability. I have over 1,000 hours on the 1kw, and about 300 on the 2. Other than oil changes, and filter changes I have never had to do any maintenance in either of them. I actually got the 1 as a throw away, figuring it would be toast onboard in a year, but it's now 4 years old and running like a top.