Say what increase your company provides per ST exam pass... would be interesting to see the ranges. No one gets exam raises where I work (it is an actuarial dept.), we get only performance relates increases.
Payrises alone don't tell you alot though. I'd rather be somewhere that paid you £40K with £500 ST payrises than somewhere that paid £30K with £3K ST payrises.
I've worked in both systems, and I definitely prefer not having exam increases - it makes you focus much more on the job, rather than thinking of work as being perhaps the secondary objective.
Have worked in 2 companies, the first one paid around £1000 per ST pass, my current employer pays £4000 Am very glad I made the move (though obviously that wasn't the reason I moved!)