I'm a Lendrum owner but I've heard good things about the Kromski Sonata!
I bought my Lendrum, not because it was a folding wheel, but simply because I loved how it felt to spin at. I tried a bunch of wheels and it was a draw between the Schacht and the Lendrum. The Lendrum was cheaper and had a few other things I liked, so I went for it! The portable part was just a perk (though I cart it around quite a bit...)
I have yet to regret my choice - whether you never want to move your wheel or you'll be taking it out everyday - Try to find out if there's a spinning guild in your area or if there's a shop or individual that has a spinning meet. Go and show up on a meeting when they'll have their wheels there to spin (ours is every 4 weeks, but it's a weaving and spinning guild), if it's anything like my guild, the members will be more than happy to let you try their wheels and help you make a decision!
Try to find a chance to try out whatever type of wheel you choose to buy before purchasing if possible, it seems everyone likes a different kind of wheel for a different reason.
Good luck choosing a wheel!