With agitator-less washing machines are very good at tangling your clothes and ruining things because of it. I would really think twice before buying one. I have had 1 for years and HATE it.
A front loader is good for saving water and is more gentle on the clothes, but you cant just "pop" something else in.
I would never buy a washer/dryer in 1. I had 1 a few years ago and neither function was very efficient.

I would buy a either a front loader ot a top loader with agitator, as big as you can