Ive used Alpha pots and they didnt suck the tone out of my pickups. CTS may last longer or be more sturdy, but as far as I can tell they dont sound any better than Alphas.

What pots do Strats use?

Single Coil pickups and brighter-sounding pickups (think Strat, Tele) use 250K Pots. Darker-sounding pickups (P-92, 43-Gauge Big Single, P-90s, and Hum-Cancelling P-90s) use 500K Pots.