I'm not convinced spending the extra money gets you very far. YES there is a lot I junk on the market, so go cheap, and get poor performance and reliability. Every reef keeper gets excited when they see skimmate forming. But experienced guys know the difference between a CPR bakpaks and a higher end skimmers MUCK.
That said, the ASM skimmers are simple, pretty quiet, and work well. I found the cup a bit tricky to take off, particularly if it was brimming with skimmate. But, not so much it was a hindrance. Do the $20 gate valve mod, and you've hot a pretty nice skimmer. Lots being sold for cheap.
Reef Octos work very well. Personally, I would not buy one again. I have the SRO3000INT. It's a beast for sure. HOWEVER, the Bubble Blaster Pump is suspect. Mine conked out several times. IF you unplugged it got routine weekly cleaning, good luck getting it to start again. Took 15 minutes of tinkering and I'd have to submerge it while running to keep it going. A mess to say the least. The Coralvue company was EXTREMELY ACCOMODATING! They took my serial number, offered a few solutions, and when they didn't work, they replaced the pump.
Here is my problem, the old pump would konk out inexplicably from time to time. The last time it did, I was on call, and leaving for a weeks vacation the next morning. Having to fart around with the pump for An hour at midnight when I should have been packing was not fun. Leaving my prized fish and corals for a week with a suspect skimmer pump was unnerving. I had read online that there were some Bubble Blaster pumps that were having this issue. Enough to raise attention. Meaning, there are some time bombs out there ticking from the generation I purchased.
Conspicuously, my replacement pump is of a NEW different design. IF the company knows there first run of pumps are suspect, they should offer a recall as most other manufacturers would. Not take the "wait and see" approach. Just my opinion. Like I said, they took care of me quickly. They will however, remain suspect in my eyes. I don't really care what they or anyone reading this thinks of me because I AM THE ONLY ONE responsible for my reef. All the emails and replacement parts in the world can't replace one of my specimens should they succumb from equipment failure.
I like the Skimmz line if skimmers. I'll probably try them next. 3-4 years down the road when I do another tear down.
Sorry for the rant, but the information may serve you well merely as food for thought.