I've no experience of these, in large part because I wouldn't buy a refurb'd PSU.
I've no reason to doubt Scan's ability to get a PSU refurbed properly, but
unless it's done right, and thoroughly, a PSU failure has the ability to do a LOT of very expensive damage elsewhere in the system.
It is an economy that, for me, just isn't worth taking.
I won't buy refurbs, from Scan or anyone, but I would say that a good refurb is a safer bet than many 'budget' PSU's, which personally, I won't touch with a bargepole. I've even had jobs where someone wants me to spec up, acquire and build a PC for them, and when they've 'economised' on the spec with cheap PSUs, I've walked away from the work entirely. If it blows, I know who'll get the blame, and be expected to sort it all out. And I'm not prepared to chance it.
So, personally, while probably a lot better than 'budget' PSU's, it's an economy too far for me. And yeah, brand new well-known name units can blow too, but (
IMHO) it's much less of a risk.
So, I'll pay the extra £20-30 and buy new units. For the peace of mind alone, it's worth it.