Dixon's run is usually worth reading with the occasional meh story. When he was on point it was probably the best Punisher outside of Ennis and the Archie crossover.
Baron was OK. There's not much to say about him. His passion was clearly in creator owned work and I suspect his Punisher and Flash runs were done for the paychecks, but he never half-assed it and was genuinely putting serious effort into producing entertaining antihero action stories. End results are worth looking into if you're a fan of the character, but don't expect to be blown away.
Potts was sort of hit or miss. His run can be entertaining, but the quality of the stories is arguably inconsistent depending on who you ask. Your mileage may vary.
The crossover with Archie is a must read. Not even kidding.
The original mini by Grant and Zeck and their "graphic novel" "Return to Big Nothing" are strong and recommended.
Everything else is all over the place quality wise. Abnett (yes, THAT Abnett) did some decent fill-in issues here or there on the ongoing and sometimes complete unknown writers that you've never heard of would produce some kinda cool stories (like the one where Frank is stranded in Alaska after a plane crash and has to survive with nothing). It's worth reading random issues because you might find some surprises here or there.
What you definitely DON'T want to read is the "Marvel Edge" (precursor to Marvel Knights) era that came out in the late 90s after all his ongoings were cancelled and he got relaunched with a single book. This was when he joined the mafia, then died, then came back as a demon hunting ghost with magical guns that shot fire. Not making a word of this up. It was RETARDED.