I'm the same with balljoints, only replace if necessary. The originals usually last the life of the car TBH. The pattern ones are shite. The ones ATP use are shite from the beginning 
The 'life' of the car being 100k ish...
The GM balljoints last far longer. On all my Omegas, I only ever had 1 (genuine GM) get any play. "I" (well, Gixer, as he has a press

) used to press in a new genuine GM rearward bush (fronts always poly'd) and pop it back on (or in my case, we always had a spare set already done, so could just replace the wishbone and the removed ones could be refurbed at leisure, and put into spares stock.
Yes the ATEC arms from ATP are cheap and cheerful, but with the poly bush mod they are a cost effective solution. Especially when you consider that the genuine arms each cost more than a scrap Omega. Even refurbishing the factory arms with genuine VX/GM parts costs far more than the ATP wishbones.
I think Chris and I were paying £14 per side, for the rearward bush. Suspect thats far more cost effective that a new pattern wishbone that doesn't really last
Speaking personally, I have fitted ATP arms to my own cars and have always found them to out perform their price point.
They do seem to have a short life compared to what I used to use (completely ignoring fornt bush, as thats irrelevant, obviously)
For anyone already on pattern wishbones, the economics change though, as genuine wishbones are probably outrageously priced.