I have both Origin and Solus. Multiple Origins in short and long. I like Zermatt as a company.
I wanted another Origin short action and stumbled across a local store selling $640 Solus actions….No FFL fee or shipping. Decided to give it a try. It was a no brainer. If I didn't like it I could sell it at no loss with that price.
Origin is available in long and short actions, bolt heads, bolt handles, and some other parts are interchangeable. Parts are easy to get and Ray at Zermatt answers the phone and emails for customer service and stupid questions quickly and efficiently. Zermatt has reps at some Expos, events, and shows. Scope rails are removable and have options for MOA cant.
I have had no issues with the bolt hitting scopes, I tend to mount big scopes in 1.26" high rings for clearance and a slightly more vertical head placement. If you use scopes mounted as low as possible/ bell tight to the barrel you might run into scope/bolt handle issues but I haven't seen it anywhere. About the same as a Rem700.
The recoil lug is replaceable/removable allowing the Hunts Long Range lug to be used allowing fitment of TL3 shouldered barrels to maximize versatility/ broaden choices on the used barrel market.
Solus has 60 degree bolt throw. if that matters. Actual shooting in a hurry I don't notice the difference. Small .223 bolt face is hard to find, just becoming available. I believe the Solus has the option of also using AI magazines as well as AICS. Aero is a bigger company, I expect parts availability to get better. I have no experience with customer service. Scope rails are integral to the action. One less thing to come loose, but no options to replace. The trigger hanger is ok but does not fit in all chassis/stocks, you might have to grind out material for clearance. That modifies a stock and potentially hurts resale value if you buy/sell/swap a lot. I personally haven't had trigger hanger clearance issues—yet. The integral recoil lug is kinda nice if you switch barrels a lot or want a switch barrel rifle but hasn't been an issue with me.
I started years ago with Savage actions. It got me started rebarreling and I loved my time with them and the Savage community then. Later I became frustrated with the ever changing specs on bolt parts, action lengths, and lack of interchangeablity. Savage shot themselves in the foot trying to become Remington. My barrel inventory was a major bonus when the Origin came about.
So, long reply. A novel of war and peace (piece?). Both are incredibly accurate and well made. Fit and finish comparable. Both are smooth and precisely made to tight specs. I like both but prefer Origin for now. Parts availability and customer service matter. If the price really matters, and you find that great deal on the Solus, it will get you in the home built game with no real deficiencies. Close your eyes and open your wallet. Life is good, remember THESE ARE THE GOOD OLE DAYS. If you buy smart at good prices and change your mind, you can recover most or all your money on resale. Way ahead of racing or most any other hobby.
Just be aware, home rifle building is probably equivalent to heroin or crack. Way beyond the chips that you can't stop eating with just one.
Just my experiences and opinions. If we ever meet you owe me a cup of coffee lol, if you can still afford it after this.