You could clean up the Hovabator and buy a couple of secondary thermometers to check and make sure it's still working! Replacement parts are usually quite reasonable and easy to change out in Hovabators as well.
As far as my favorite incubators, I love my Nurture Right 360s! They are reliable and they're great for hatching with kids because they can see everything! I also like my IncuView which also has a clear plastic lid for viewing. Of the styrofoam incubators I always recommend the Hovabator first so it's definitely worth cleaning your old one up if you don't want to invest in another incubator.