you got to ask yourself if you need an isolated power supply. some pedals have problematic power requirements, like ehx pedals (especially the digital ones). cannot daisy chain, cannot whatever. pedals with a high current draw are not suitable for some power supplies as well. the mxr dc brick is not isolated, it is just a daisy chain that looks like a box.
hum is more likely when you connect the power adaptor to the same wall socket as the one which your amp is using, if you are using some kind of multi-plug. but if you play at a gig, it is likely that your power source will be very noisy.
i used to own the t-rex fuel tank junior, but despite being isolated it caused a low hum (which is different to noise) when engaged, which even my china boss-style adaptor didnt cause. i sold it and got a godlyke power-all.
for 18V pedals you might want to use a Y-cable. the fuel tank came with one of this.
older versions of the 1spot have been known to be noisy. but i gave up on 1spots completely after i discovered that some pedal manufacturers explicitly state that use of the 1spot will void all warranty.
yup if you have specific needs you need to import. at least MOST dealers here do not jack up the price of their products IF and WHEN they bring in the stock. sometimes, the dealer marks up their stock such that it is more expensive or the same as buying overseas plus shipping.