I think the Opto Flows are great. Got a fairly opaque pink around 168g, and it just seems to fly better/easier than some of the Wraiths I've thrown, although I like the Pros and E* Wraiths. Never thrown a GL Flow. The GL River is money, IMO. Similar to a Leo, but has a good bit more glide. It really seems to want to stay in the air. The Opto Striker has also been a good disc. I personally throw it for a bit faster Teebird type flight. The Opto Pain I liked at first, but it just didn't feel quite as well in the hand as my champ gators. I had an Opto core, but didn't really get into it either. As I've been attempting to disc down and minimize molds, the only ones that I currently carry are the GL Rivers, and then an Opto Striker. I noted this in an earlier thread, but will state here as well: An Opto Striker and a GL River can be a great fairway combo. I also tee off with either, depending on the hole.