5 hrs to Coed-y-brenin and totally worth it.
I'd ridden there before and I think it's fine, perhaps a little overrated, but I had to go up that way for a REC first aid course in November last year so went a day early, figured I'd drive it with as scenic a route as possible, get a ride in and find my B&B.
Got there around midday on a Friday, deserted car park, not a single sole on the trails, cold misty day. Rode the Tarw and MBR trails in one hit and just had one of those rides where everything came together and flowed perfectly.
Probably the best ride I ever had. 😮