All I can say is that used with S-33, you get a yeast blend that flocs ok (not like Notty or something, but the beer fully clears in the usual time), and if fermented at 22/23 gives lovely British sort of esters. These initially can be a but much (by initially, I mean right after carbing up, before any maturation time) but after a couple of weeks are bang on.
I did a sort of old ale / strong bitter; you know the sort of thing, crystal malt, decent pale malt (plumage archer), bit of melanoidin, homemade #3 invert, fuggles) with this combo and it was the first beer I've totally formulated and brewed myself that really, genuinely, stood up there with proper cask. I've done very similar recipes before and they never turned out this good. The yeast really made a great contribution.
Both s-33 and CML Celtic can be had at a reasonable price, so 2 packs in a 23L brew aren't that much more than a single pack of Windsor, so it's worth a punt if, like me, your haphazard brew schedule means liquid yeasts are often a non starter ( no pun intended!)