There are so many variables with the plates and wings. You can buy complete systems or you can piece the components together yourself. Deep Sea Supply offers complete setups that are at great prices for the complete rig. My wife and I have three of these, 2 single rigs and one double rig. Oxycheq rigs are popular as well, many people put together their own setup using their wings, with other plates and single tank adapters. I have an Oxycheq double wing with an aluminum plate I made myself. Dive Rite offers some complete rigs with aluminum, and stainless plates. They also have another type of "plate" called a transpac. It's a rigid fabric covered type of plate, maybe an owner of one can describe it better.
Obviously Halcyon, OMS, Golem, HOG offer complete rigs as well.
There are differences to consider, but some things are splitting hairs. Among plates, you can choose stainless steel, aluminum, kydex (Deep Sea Supply), or the transpac (Dive Rite).
The plates have different bend angles, surface finishes, length options (Halcyon, and DSS), and other features such as rubber molded inserts in the webbing slots (DSS). These rubber inserts lock the webbing in place, other plates will use tri-glides to accomplish the same thing. You can also get plates in various thicknesses (Fred T), and with slots for handles along the sides (Hammerhead). You will also have to decide if you want to use a single tank adapter (STA) or use a sta-less design. I believe the Hammerhead plates can be used without a STA, check their site to confirm this.
DSS single tank rigs are designed to be used without a STA, Oxycheq wings can also be used without a STA.
I prefer the DSS design, the STA setups have their fans as well. Just search for more info and debate.
Wings all come in different shapes and amounts of lift. The are made from different fabrics for their outer covers, the inner bladders come in various thicknesses, and are also made from different materials. Halcyon uses a different inner bladder than DSS and Oxychec do. DSS uses a thicker inner bladder material than Oxycheq does.
All of this can be splitting hairs when comparing them. I will say that I prefer the DSS designs, I'll add that I am happy with my Oxycheq wing. I prefer the DSS stuff however.
Some other things you will have to decide on are donut vs. horseshoe.
I happen to have horseshoe wings for doubles and single, my wife has donut shapes for her double and single rig. To be honest it doesn't matter to me one way or another. Search, and you find all sorts of stuff on this.
You'll find that you can get good deals on horseshoe wings, because everyone seems to think that donut wings are the way forward. People sell the horseshoe shapes to buy donut shapes. Be on the lookout for great deals on horseshoe wings.
It really makes no difference to me.
Another aspect of wings are that some have zipper access and others are sewn shut. DSS offers both, their donut wings are sewn shut, and their horseshoe wings have zipper access along the top.
Their inner bladders are very thick, and their outer covers are made from ballistic nylon. Zipper access or not doesn't really matter either.
People often mention that Halcyon is too expensive. Well their stuff looks great to me, and seems worth the price. They're no more expensive than top of the line recreational BC's. Compared to piece-it-together setups that people shop around for and assemble, Halcyon is more expensive. I'd rather have a complete setup from the same manufacturer. DSS has more shapes and sizes than anyone else.
HOG is probably the cheapest complete setup that you'll find. I've never used one, but people seem to like them. I've read that their inflator is slower to inflate than others. Search and see if this is still the case. If you're on a budget and want a complete setup, look into the HOG rig.
No matter what you get, I'd replace the OPV with the DSS one. It's only about $20. Some manufactures have had recalls on their OPV's, depending on who their vendor is.
Just get a DSS one and don't worry about it. Theirs is really nice, and well worth the upgrade. I put one on my Oxycheq wing.
My recommendation, get a complete setup from the same company. I can't think of a compelling reason to piece together everything from different companies. Just save up and get it correct the first time.
Get the correct size wing for your needs. Don't get too big of a wing, keep it streamlined.
There are way too many threads on this, search and you will find.
-Mitch
