The distributor here in the US runs them with Ypsilon gear. Probably not appropriate from a budget perspective but informative in terms of sound.
they are not particularly bright but also not warm. A neutral to slightly forward or slightly laid back sound profile is what I would go for with an amp.
i have a pair of Vertexes on order and plan on driving them with a Canor AI 2.10 integrated. ARC is brilliant. If you want a touch of forwardness, Musical Fidelity SS could be brilliant at a modest price. If you want a touch of warmth, AVM would be a fine choice. Rogue would also be a nice option.