I have used both the convection (heat rises) and forced air flow types. They both make fine jerky but, hands down, the easiest and fastest to use is a forced air flow dehydrator. The convection dehydrator requires you to to swap trays (top for bottom, 2nd from bottom for 2nd from top, etc.) every few hours or the bottom gets rock hard while the top stays chewy...that being said, I used one of these for over 10 years with no problems and it was pretty much the only kind available at the time.
When I finally went forced-air-flow the drying time dropped dramatically. It took a little experimentation to find the right temps for an overnight dehydrating...but I would never go back to the old one I had if I had a choice. I think this is close to the one I have been using for the past 8 or 10 years with great results:
BTW - I probably make 30+ batches of jerky per year.
The one I use is a Excalibur. Almost all versions get 5 star ratings. 5 tray one will handle 5 lbs. easily. Only thing is to get even drying, every 1 1/2 hrs., I rotate the trays top to bottom and front to back. It's no big deal. Had mine for probably 10 yrs. without any problems. Temp goes to 165.