It's really down to when you want to / have to travel as to their cost.

Sure you can pick up a £1200 CW seat in a sale, but you might be travellling out of the period and seats are £2k+ minimum.

I'm flying to BOS in 2 weeks on a £460 Y ticket as WT+ was over £1800 that week (£768 the following week). If there were any CW redemption availabilty, £1345 for the Avios and taxes would be a bargain so to speak.
I've also just spent 4500 Avios + £15 in tax on a MAN-LHR-AMS flight. Same flight was priced up at over £200 in Dom/ET and £500 in Dom/CE. Bargain there in my opinion.