I went to a guitar store recently that sold Strandberg guitars and Mayones guitars. The Strandberg I played was flawless but the Mayones felt like it was shoddily put together for some cheap mass production run or something. Bearing in mind that this thing was a good £1800 I really don't think it should have had fret buzz all up and down the neck and whatever muddy pickups it had on it. I've read reviews on these guitars saying they're fantastic, so is it possible that this one was a cheap Chinese copy or defective or something or is this sometimes possible with this brand?
Sometimes guitars are just poorly setup. Sometimes the action is so low that noobs fret out just by touching it. It happens.

Sometimes the mayones is a setius.
Prs se Holcomb is the answer
They are the cheapest mayones. But, it could just be a setup issue.

As for the sound it really depends on what pickups it was shipped from the factory with. If it was omgs or sd nazgul sentients then it shouldn't sound that much different then the strandberg.
Prs se Holcomb is the answer
cool cool.
i wouldn't pick a setius over a strandberg personally either tho.
Prs se Holcomb is the answer
I'm not a big fan of the Setius either. The one I played was a good guitar in itself, but was nowhere near as good as any Regius I've played. They're not bad guitars, but at that price, I think there's better stuff, including the Strandbergs. 

Going to agree with AcousticMirror that it could've been a bad setup, but the pickups shouldn't be bad. If it was used, it could've been a fake, but that shouldn't happen in a store. There are fakes out there though. It's also always possible one slipped through QC or just wasn't built to the regular standards. The only things you can do is give the company a second chance and hope the next one you play is good, or walk away and never consider the company again. I prefer the first one. :P
that setius headstock. oof. it's like they don't want to sell any.
Prs se Holcomb is the answer
a bad setup can make the guitar sound like total shit. one of my most expensive guitars came horribly setup, every note sounded muddy and dead. I was surprised how even my $300 Schecter sounded better.. I changed the strings, and raised the action and now it plays and sounds excellent.