I don't want to get into a pro/con AV123 thing, but I do want to point out something. You're not really with the same manufacturer at all right now as AV123 and Onix went their separate ways a year ago and the ELT525 series has very little in common with the Onix Reference series. I actually think the ELT525 stuff is pretty good for the price, but the center channel is a bit of a weak link due to cabinet resonance. If you want to keep that I'd recommend investing in a sheet NoRez from GR Research or precut kit from Skiing Ninja. It will make a world of difference in dialog intelligibility.
I've demoed the Paradigm Atoms and thought they were decent, but would probably spend the extra $150 on the Mini Monitors because I thought they were a better value at their price point. The ELT525M's are a touch to the warm side of neutral, and the Atoms probably expose more detail, but I find the ELT525M's a little more fluid and musical in the midrange, which is more important to me.
The Ref 1's are a completely different story. The drivers are a bit higher quality than the previous two contenders, but the crossover design is only so-so. Some like a forward-tilted response, but it's not for me. Skiing Ninja sells a crossover upgrade for them that isn't just higher grade components, but a whole new network design by Danny Richie, and I think it's just a night and day difference in the Ref's. I really liked them a lot in their upgraded state. The price of the upgrades puts them in competition with some pretty good speakers though, so that option is a whole other debate.
disclaimer: I'm an onix dealer, and while I try to be objective and unbiased in comments about the brand, I feel I should disclose my affiliation.
I also demoed Studio 20's and wasn't in love with them. (it was two years ago - V4 I think?) They do a lot of things objectively well, but as an overall experience I actually enjoyed the Mini Monitors more. I found the Studio 20's very smooth and extended up top, with good detail and resolution, but they weren't very dynamic and loud rock felt compressed to me. The image was wide, but stayed up along the back wall and never jumped out at me. "Too Polite" occured to me at the time, if that makes any sense. I can certainly see how some may like their sound a lot though. As I said, they were certainly refined and detailed.
I personally won't be buying from AV123 anymore for a variety of reasons, but if you purchase something that isn't still "in development" and doesn't have an amplifier in it, then you'll get a quality product. If you want to know what the issues are, it's not hard to find those threads. I don't want to make this one of them.
