Ruud, Rheem is a cheaper brand .... it is harder to work on but seems to run ok... ya might check out Frigidare, TRANE, American Standard, these seem to be more user and service friendly and very reliable. Trane you can get an extended warranty for 15 years!!
Janitrol, made by Goodman is very cheap, and there is usually the old saying you get what ya pay for, this is my opinion,
my best suggestion is... if they have a electric spark ignition, don't buy em. Ruud should have the HSF ignitor though