so, i've been running ENLEE frame protection for the past couple of weeks and i can say i'm impressed. it was extremely easy to install, very stretchy when blasting it with a blow dryer, and seems to do its job. i wouldn't install it without heat though. also, i bought the one with a topographic map because i thought it'd look cool, but my frame is dark blue so it came out horrible 
anyway, does anyone have long term experience with this brand, or another inexpensive alternative?

I just use 3m ppf wrap on all of my bikes. It's cheap, does the job and barely visible unlike the one you used. For downtube and chainstay protection on mtb/gravel bikes I use 3m rubber mastic tape