Totally unknown quantity - and by that I mean both product and vendor.
Some of the Shanlings they sell I have seen before, but the rest would require a real leap of faith to buy.
What with that and tubes/valves being sent by post, 22% or thereabouts VAT and duty to pay, shipper's handling fee to administer the payment of the taxes, potential for a lengthy delay while they're detained in customs, and what happens if you unbox it and it goes 'phut' or packs up after a few months, rather you than me...