I can't say enough for my Lendrum. It's one of the larger of the portable wheels, but still takes up less floor space than a 'regular' wheel.
The Majacraft Little Gem (not for me, but I know some who love it) and the Schacht Ladybug are a couple wheels not considered folding wheels but are considered portable because they're so small, you could take a peek at those too.
Size was the second most important factor for me when I was looking to buy a wheel (performance being the first), as I'm in a small space myself. I know the Lendrum isn't as small as an Ashford Joy or a Majacraft Little Gem, but after trying multiple types of wheels at a spinning meet - both folding and not - I much preferred the Lendrum to any other wheel. Only the Double Treadle Schacht Matchless was a contender, but it was big and too $$.
My suggestion before you buy any wheel would be to try it and maybe a couple others (even some non-folding) just to have something to compare it to. I did this at my local fiber guild spinning meet. Sometimes you can find a spinning store that will let you try some different wheels.