Generally very impressed. Assembling the R-400 is pretty easy and took about an hour all told.
The machine is quite large, so isn't ideal for a smaller household. It doesn't fold up but can be stored on its end and has wheels to maneuver around (though they are fixed, which can be a bit of a pain, when trying to turn the machine).
The R-400 computer and screen give you a lot of different options, from manual, program and race, you can set different amount of resistance and length of row. This makes using the rowing machine more interesting to use. It is powered though the mains, so this is something that should be considered when buying.
The seat is comfortable and as is the rowing position. there are vents to allow air to hit you if you want when rowing. The R-400 is relatively quiet, certainly quieter than most air rowers, I have used.
Generally I am impressed but there are a couple of niggles. The foot rests are not as comfortable as I would have liked and the seat does stick a little, though this hasn't been a big issue.
A very good rower for the price but not quite prefect.