I painted first, thinking a spot of varnish on paint can be easily wiped off without an apparent trace, but paint on varnish may not be so easy. Paint on unvarnished epoxy can be vanquished with a little 400 wetsanding.

CLC's shop tips on finishing worked well for this first timer. The small imperfections really DO show up bigger on that painted finish (sand, sand, sand).

I don't have much to compare it with, but I am a little disappointed with the Interlux Brightsides. It looks great, but seems easy to chip or scratch (Of course I may be uncommonly clumsy and may not have applied it correctly). I believe I saw a strong endorsement for two part polyurethane on this BBS recently, though it is apparently much harder to apply.

Good luck.