With any incubator you need to calibrate the temperature. The factory settings can be off on even the best ones. So expect some fiddling while you get it adjusted. But I agree, you don't want to be constantly adjusting after you get it set.
I'm not sure where you are located and what makes and models might be available for you. In the US it use to be your choices were pretty much
Brinsea, Hovabator, or Little Giant in the size you are talking about, but lately I've been seeing a lot of other brands available. Best is kind of a nebulous term, depending on what your criteria are.
Brinsea are generally considered the best but they are more pricey. Hovabator are probably next, but some of that may be that a lot of the LG reviews are on the really cheap still air models. A lot of chicks are hatched in all of them.
The features I'd look for are a forced air fan, auto turner, and a decent window to see what is going on inside. After that, I'm a little more flexible. How easy is it to control humidity? Do you have to fill internal reservoirs or is there an external reservoir. Can you adjust the humidity with a dial to get some really fine tuning or is it by fiddling with sponges or rags in reservoirs? How do you adjust the temperature? I have an old-style Hovabator 1588 with those dip-switches. It's a royal pain to change the temperature settings but once I got it right it's held steady for several years.
How often do you hatch? One advantage of the hard plastic type incubators is they are easier to clean than the foam ones. I only hatch 2 or 3 times a year. If I were hatching more often I'd probably upgrade to a hard plastic one just for ease of cleaning.
I can't tell you which hold temperature the best. They don't make my model of the 1588 anymore, they changed the controls. I've had great luck with my 1588 in that regard once I got it set, but you've had a bad experience with Hovabator. I think a lot of that is luck in which specific incubator you get.
I can't make a specific recommendation for you since I'm not sure any specific make and model will absolutely hold temperature without adjusting once you get it set, but when I have to replace this one I'll probably go with a
Brinsea.