I was interested in these since I first heard about them and finally grabbed one. Initial review was from Feb, 2010 - updaets are posted with the dates they were made below.
Retailer description:Features:
Featuring an 8+ (or 8-10) balls per second feed rate.........and no batteries required.
Powered by minimal agitation of the gun, the Primo Loader helps sort and funnel as you shoot for a consistent vertical feed.
The patent pending Proto Primo Loader is the first of it's kind with a positive feed shelf designed to relieve pressure on paint reducing jams and increasing feed rate.
Comes with a clear spring lid for easy reload.
The large opening works well with Proto Alpha pods for the ultimate paint carrying system.
Large capacity durable shell holds 200 paintballs.
First Impressions:It's got a sleek external design, nice silver Proto badges, and a flip top lid that stays up via a spring. The shells feel very sturdy/durable, too. Not like a cheap plastic.
Packaging:It's a non agitating hopper that comes in a box nicer than what most guns come in, probably could be a couple bucks cheaper to slap it in a plastic bag with a folded name stamp instead.
Tacamo/Archon copy?I heard a lot of people before this was released saying how it was a ripoff of the shelf hopper Tacamo made. It is not. The shelf is a seperate piece that has a very unique design. It is a long shelf that angles down towards the back of the hopper from the nose. The top has a 'channel' running down the center of the shelf from the nose end of the hopper to the back of the hopper. Also the bottom of the shelf has a ridge that runs the length of the shelf. I don't really know how else to describe it, but the ridge is shaped like a serrated blade, only the serations are much larger, make sense?.
Size:It's a 200 rounder, nuff said. I lined it up with two other 200 round hoppers to show a profile size comparison. The Primo is a tad thinner than both the SSL-200 and the VL200 too. I put a 50 rounder in there as well for comparison.
Size comparison:
From left to right(GXG pocket hopper, VL200, Proto Primo, Tippmann SSL200)
Performance?I tried this on two markers to give it a fair test. First with my Azodin KP. It sits a little high for what I like, but it's not uncomfortatble.

I shot this thing as fast as I could and it didn't skip a beat. Perfect, especially considering this is what I bought it for.
Next I ran about 2 pods through my ND freestyle with it. I was in semi only and with the eyes on I didn't break a single round. I did have some skipped shots when I really got on it, but when I was shooting conservatively, 6-8 bps, it fed incredibly well and very consistantly. It's an incredible difference over a VL200. I'd actually put it on par with a revvy.
Overall?For $14.99 you get a hopper that doesnt' take batteries but feeds almost as well as a reloader or revvy. It's a good design, a nice value, and it's well built. I'd like to see a 100 round option as well, but this is perfect for my KP for now. Nice job Dye.
*UPDATE 5.25.2010*After a full day of hard play in crummy weather on an Automag RT the Primo continues to impress me. I went through just over 2300 rounds on 5.22.10 in the mud at TRP with this setup and I have to say, the Primo is badass. Now, bear in mind that my RT is euro highrise so there is a higher ballstack than on, say, a new ULE mag. That said, I had many occasions throughout the day where I really laid it on the trigger. The only time that the Primo missed a step for me was when it was down to the last 10 or so rounds.
*UPDATE 8.2.2010*Saturday, 7.31.10, I took this setup to the UWL(Automag RT classic/Primo/Marbs). About 1200 rounds in two matchups went through this thing and I still have yet to bust a round in the hopper or have it jam on me. I haven't had to shake or rattle it to coax a round out(except when it gets down to the last 10 rounds or so). I didn't skip a single shot and this was in a tournament where I was putting out some decent BPS.
This pretty much concludes my testing of the Primo. Honestly, I don't see myeself using another hopper.