The flatbed one is great you won't regret it.
I better get 25l - 30l,or above. My microwave utensils and occasional pizza don't fit in small microwave.
700w you will regret buying it, You want at least 800w or better still get 900w.
Thanks op been looking for a new microwave,but ordered flatbed 1 for £50
Basic, but cheap, does the job, so hot from me, difficult to find a cheaper one.