I have tested almost every solution there is as a printing surface – several PEI sheets, glass, mirror, Ultrabase, etc. Fiberglass surfaces are *by far* the best I have tried so far. They do not require any kind of adhesive, everything sticks perfectly on them while they are hot and then just pops off on its own when the plate cools down, and I am getting amazingly smooth bottom layers. I only have to use underspeed to get a first layer adhesion when the first layer is very complex, otherwise I always print the first layer at the same speed as with the rest of the print. In this video, you can see that you can lay the first layer down at 150 mm/s and it will not break a sweat (PLA @ 50°C plate temperature).
Everything sticks to the plate at about 20-30°C lower than with most other surfaces. PLA works great at 40-50°C. Do not try to go over 80°C with ABS because it will literally fuse with the surface and you will have a lot of trouble getting it off!
I got pre-cut 310×370 surfaces for my Tevo Tornado from AHLtec (Germany).
3D printing on GFK (fiberglass), first layer @ 150 mm/s