I've got a Fowlers - 2nd hand in excellent condition on e-bay. They are often on Gumtree too.
Works fine, and you can buy extra layers from Ebay sellers such as shell**blue and ozfarmer
The donut shaped ring for making fruit leathers is a litle akward to use, in that they don't roll up neatly
I love the cozy sound mine makes (especially in winter when the warm air sends it's nice soothing aromas out) - it seems to set off a Pavlovian response - 'Ooohh, I'm going on an overnighter soon....

'
More expensive brands like the Excalibur have rectangular trays, so you can cut your leathers into straight sided strips
Excalibur seems to be the top of the range brand, and people who have them seem to swear by them, especially if they do a lot of dehydrating
The Sunbeam circular shaped model is one a lot of people seem to use as well
It's best to get a model that has a thermostat, so you can regulate the temperature, as some things are better at a lower temperature for longer, and some need a higher temp to kill off bacteria (like meat)
I've seem some inexpensive types in 'CopperArt' type shops that don't have a temperature control