Skimmer Opinions

[Captainhemo]

Hi All,
I'm planning on upgrading my skimmer (currently only have a CPR BakPak) in the near future and am looking for some feedback/suggestions. My current system volume is about 70 gals, an upgrade down the road isn't out of the question.
I have been looking at the Remora Pro, the Deltec MCE 300, and the Tunze DOC 9005/9010 skimmers. I am looking at HOB skimmers as I only have a 20 gal sump so space is limited here. Vertical clearance is also an issue.
I could probably fit the Tunze's in the sump as they are very small but haven't heard any reports of how well they fiuction.
I have read a few posts that report great performace from the Deltec. I also like the idea of the internal pump and not having it hang insdie the tank.
I could probably pick up a used Remora Pro for a lot less money, these skimmers seem to be quite common on the " for sale" forums. Is there an issue with these?

I don't mind spending the money if the performance and epandability warrant it. On the other hand, if a used Remora Pro is going to do as good a job as one of the others, I might as well go this rooute.
Anyone have any opinions etc regarding these skimmers or any others I should be looking at ?