I am no dehydration expert, but I have read a lot of reviews and done a fair bit of research. Nesco and Excalibur are the two that I have used and are the most popular out there. Both have a good track record, but the Excalibur are definitely a step up from Nesco. You will pay for that step up, at least twice the price. Read below for specific models and my take on them.
Nesco FD-37A $35 at amazon.com
This is a new dehydrator I noticed on amazon. It is very inexpensive and seems to have a lot of favorable reviews. It has a fan, which is essential, but it does not have a thermostat, so it only runs at one temperature setting. You will have much longer dry times for some items. I have not done enough testing to see if there is a difference in quality of the dried item, but I do know that every book on dehydrating I read, they talk about using different temperatures for different foods. You will have very long dry times for some items. I think for $15 more, it is worth having the thermostat.
Nesco FD-60 Snackmaster Express 4-Tray Food Dehydrator $50 at amazon.
This is the new version of the first dehydrator I got over 10 years ago. It is a great dehydrator that works well for all types of food. It has both a fan and thermostat. It also comes with one fruit leather tray for any sauces you might what to dry. I use these for dehydrating salsas, tomato sauce, pesto and for making bark. I would recommend getting a few extra fruit leather trays, you will use them. You can also use parchment paper, but you have to cut the hole in the center and trim off the sides. In addition, you can’t fill the paper too much or it will spill over. The trays have a lip to them. Nesco has a slightly larger and more powerful version of this unit for $70.
Excalibur 2400 4-Tray Economy Dehydrator, Black $120 at amazon.
Now if you are serious about dehydrating, and you have extra cash laying around, this is the one to get. Excalibur is the industry leader. The square trays will hold a lot more food, for just a little more counter space. Foods dry faster and more evenly in the large box. If you want to check a tray that is at the bottom you don’t have to take off all the trays above it and put them on the counter, you just pull out the tray you want to look at. In addition, the square trays make it easier to use parchment paper for saucy items. The non-stick sheets that you use to make sauces and leather are amazing. With the plastic ones from Nesco, you have to coat them with oil each time, and that oil leaves a little residue on the food. It has never bothered me, but oils go rancid faster, not a big issue for most foods as the amount is small, but for fruit leathers, it is not ideal. The non stick sheets are amazing. I have never used oil and I never have sticking issues. I bought the off brand type. 9 sheets for $12. If you buy the official ones from Excalibur they are 1 sheet for $17. The price difference is amazing. I am sure the Excalibur sheets are better in some way, but I have used my off-brand style for over a year and they always work amazingly well. I spent the extra bit of money for the timer, and I have found it is not worth it to me. I don’t cut my food too evenly, so I have to take off some items sooner then others.
Best of luck on your dehydrating adventures. It will open up a huge array of possibilities for your meals.