I have a 1583 listed in the auction section here (link in my signature line). The 1583 is identical to the 1588 except for the thermostat. The 1588 has a factory pre-set thermostat while the 1583 has a wafer thermostat. Personally, I like the 1583 better, the wafer thermostat with the 'key' is much easier to adjust if needed. It took me forever to figure out how to adjust the 1588 (the factory pre-set is not always set right). I'll be making a cabinet-style incubator and won't need the 1583...plus I need to sell it to get the money I need to buy the thermostat and heat element for my 'big' cabinet-style incubator.
I've had the 1583 for about 1 1/2 years. I've used it pretty regularly, but it has a lot of life left in it. I've not had any problems with it, like I said, I just don't need it anymore