I cringe whenever I hear of people who are still printing on kapton tape. Honestly, I found it to be so frustating that I would probably find something else to do with my time if it was the only print surface available. IMO, there is not ever a reason to print on kapton when glass is readily available everywhere and very cheap. Why be constantly replacing tape and worrying about getting it down with any wrinkles? I have found all plastics stick easily to glass and glue stick. Plus you can pry off the print (if it does not self release when cooled) without damaging the kapton.
IMO- do yourself the biggest, easiest favor of your 3D printing career and start printing on glass.
I will be experimenting with PEI soon but if it can be damaged with a paint scraper I will probably go right back to glass.
SD4 w/ RUMBA, E3D Volcano, all bearings, glass bed