I must be out of touch because I've not heard of Vantage. I always self-build, but if I wanted off-the-peg, I would go for fairly well-known, stable and profitable brand that is likely to be around for the duration of the warranty. Nothing is certain of course - just look at Tiny, Carrera, and so on - but I can't see Dell, Mesh, Evesham, et al dissapearing tomorrow.
I would try to find out more about the company before spending a substantial amount of money. Vantage *could* be very good, but I don't know.