Depends on how much you want to spend. I have ad the best luck with KKM and Stormlake. Haven't got my bar sto in yet but they always get good reviews. (Just way too pricey when you buy a gunsmith fit barrel). We have a lonewolf that I have no complaints with either.
Me personally, I am not a big fan of ported. I reserve that for the big boy rounds like 454 and 460, etc. I have one extended barrel and I saw a little bit more accuracy. I have a KKM in my G20 and it is noticeably more accurate then my factory barrel. Nice looking too.
i have a bar-stol in mine and a glockworks fulcam triger in it too. i get of a rest at 25 yds one inch 3 shot groups with it and i also got a lw 40 barrel to and it shoots of the bench rest one groups to
I've got a Lone Wolf 5.15" barrel for my M20. It sticks out a bit but not enough to matter for carry, but it does give that extra little bit to velocity.
You can purchase a 5" or 6" slide from LWD for $260 stripped.
You can get a 5.15" or 6.02"/6.52" barrel from LWD for $124 everyday including Christmas.
Only you can decide it it's worth it to go "long slide" but for field use in a 10mm it's hard to beat the added velocity.
I'm thinking about keeping my stock length slide, putting in the 6.52" threaded barrel and machining a custom "slide profile" barrel weight that threads onto the barrel and blends it all to the slide. The reason is because the added mass would delay slide unlocking, but once open the reciprocating mass would be the same as stock. Long-slide pistols can get a little sluggish on cycling because of a greater total cycling mass.