FWIW here is my take on the Black Diamond rifles:
I have hunted with a TC Fire Hawk for about 6 years now. I have NEVER had a misfire EVER! I have hunted in rain and snow with NO PROBLEMS. The only problems I ever noticed with mine were the following:
1. Non removable breech plug (Black Diamond's is)
2. Not a fast enough rate of twist (1:38 for the Firehawk, Black Diamond is a 1:28" twist)
3. I bought a .54 caliber which has been a little harder to find loads for. (Black Diamond not offered in .54)
The Black Diamond uses the exact same action as the Firehawk did. The Black Diamond is essentially the newest version with the above mentioned changes as well as allowing you to shoot either no.11 caps, Musket Caps, or the 209 primers. Firehawk was limited to no. 11 caps (again, I NEVER had a problem with mine igniting). The action was very simple to take down for cleaning and is very straight forward to work on. The trigger was easily adjusted and the TC manual actually described how to adjust the trigger if you wanted. The Knight says it is adjustable, but doesn't want you to adjust it. That said, it is very easy to adjust too, but I knew what to look for thanks to my TC Firehawk.
I have just bought a Knight Wolverine 209 in Stainless with a composite stock and I like it alot. Is the quality any better than the Thompson Rifles? NO, other than the stock. I like the composite stock that the Knights come with, they have a nice solid feel to them.
I would have bought another TC in a second if I hadn't gotten such a good price on the Wolverine 209. I am still not sold on the Extreme Discs yet. They are quite cumbersome to deal with. I am sure that they will offer the most water tightness of any of them. Again though, I never had a problem with the number 11 caps and the stiker on the TC.
My friend has the BD and he has thoroughly enjoyed it. He has taken several animals with it and he actually prefers shooting the number 11 caps with his.
The omega seems to be well built as well. I would assume it is equal to the quality that all Thompson Center rifles have. They make nice rifles and shoot very well. With either the Knight or the TC you'll be getting an American made firearm that carries a SOLID warranty.
Now if you want a nice rifle for a low price, Check out walmart with the Remington Model 700ML. I have heard that they are selling them with an accessory kit for about $229. That seems to be a solid deal to me too. I don't know how their quality compares to the Knights and TC but I don't imagine it being a bad rifle. I have never shot one, but know of several people that have and they liked them. FWIW Firehawk