I think they are marketed by Lexmoto. They seem well speced compared to some base Chinese models. I'd so some digging and see where the engine is made it might be loncin they used to make engines for BMW. For me it's not just about cost it would be stuff like dealer support and service intervals as they can be quite low on Chinese bikes. If its a mainstream dealer that has more recognisable brands I'd be more satisfied they they have put the bike together with some care and attention than a smaller dealer that may only deal in Chinese 125s.
Maybe take a look at the benelli trk502 and the cbx500 see them in the flesh and hopefully get test ride. Honda maybe able to offer deals like last year's low Apr finance, £500 test ride initiative and 3 yrs free servicing etc. Look at it all and weigh it up sometimes a cheap purchase price can be offset by other factors.
Nathan the postman the blogger likes the voge but I personally think they are too new to judge their longevity. They could be an Interesting contender in the 500 market I like the benelli and seem to be good value.