Ayon vs. Mastersound vs. Vaic Tube SET

What is the relationship between Mastersound, Ayon, Vaic? Seems they've been using those names interchangeably. 

Also, I heard that Mastersound amps are notoriously unreliable because they create so much heat it causes the components to fail. Do they really have inherent design flaws? Also heard that their factory support is so poor which is why they're not well distributed in North America. I know there is only one dealer in Texas. 

If one is to acquire a mastersound amp, would there be any support in East cost NYC area? 
Does anyone know how the Evolution 845/ PF100 / Compact 845 from circa 2010-2013 different from Most recent model? Have they improved reliability ? 

Which Tube amps rival Mastersound ? 

Many thanks for your excellent reply. One day I hope to be an owner of a Mastersound SET. If one is able to get their hands on a used amp, do you offer any kind of service contracts  or extended warranty? How are the evolution 845 from 2010-2013 in terms of reliability ? Would you say the newer ones that produce less heat are more reliable ? Are the parts readily available from the manufacturer ? I think I would be more comfortable knowing there is service tech/dealer somewhere on the east coast that would obviate shipping if the problems arise. 
I've heard Mastersound PF100 mono blocks about a year ago with SF Elipsa SE and spretto pre. To this day I'm haunted by that magic and astounding witchcraft. Without a doubt, that would be the last amplifier I would ever buy. 
Bsimpson, I'm sorry to hear about your experiences with the MastersounD. It sounds like that unit might have had a hard life. Regardless, I wish I would have been able to help you with it. I'd love to know more of the story behind the unit like the known history and what issues you had. I'd also be curious who you worked with. A PM is welcome if you'd rather discuss privately. 

Ei, per the case detailed above, Im quite hesitant to purchase second hand tube amps. I've done that in the past prior to entering the industry and had similar issues. It seems to be an often occurrence where some of these units might be a first foray into tubes for some and ignorance can be brutal on tube amps. I would have less issue if I knew the seller and he was the original owner or at least knew the full history of the amp and all previous owners. 

The new Evolution is in its second generation I believe. It was 'evolved' from the Reference 845 which is what you will more than likely find on the used market. I've seen one Evolution 845 come up and it was swiftly purchased by a friend of a client who owned a current Evolution 845. The newest generation of MastersounD amplifiers have rounded wood accents vs the bullnose finish on previous models and also do not have the mirrored plate separating the tubes from the transformers. It simply has the mirrored plate that covers the top chassis. 

I am not in a position to offer any warranty on older MastersounD amplifiers. I can offer my support in trying to fix any issues that arise by dealing directly with MastersounD. They are quite responsive and want to see their products have a lasting legacy. 
I traded a Bryston 14 B2 and BP-20 for Mastersound PL-5 and two Mastersound 300B mono blocks plus a smidge of cash.  The Mastersound outperformed the Bryston in all categories save maximum volume.  I've run this combo for over 3 years now without incident and it powers my NOLA Metro Golds to very satisfying and delightful levels.  I don't understand why Mastersound gets poor reliability reviews as they are extremely well-built and seemingly very dependable.  Perhaps due to their size and weight owners are over-driving them expecting more than the rated 30 watts, Class A.