i had a clapton boost for a long time, till the guitar got stolen unfortunately, and one of my long time bandmates uses a first year clapton strat almost exclusively, so i have a fair amount of experience with it.
there is some misconceptions out there. the circuit is actually two boosts on one credit card size board. there is an always on preamp boost and the adjustable mid boost. i ran a handful of different pickup sets in there over the years. finally settled on the cs+ neck and middle with a vintage hot stack+ bridge, but i used a set of ssl2, aps2, texas hots, a custom set of lace sensor hot golds that donzo made for me, and an a5 set of pups i wound (.688 rods, 8k turns neck, 8.5k turns middle, 9.5k turns bridge) some worked better than others but they all sounded fine. my buddy has the stock 1st gen lace sensor gold pups in his.
the preamp boost makes the guitar high output even with something like the aps2 set, which are not high output at all. the tbx tone control (stock wiring) works better with some pups than others. i found i really didnt like it so eventually replaced it with a normal 250k/.022 tone control. the mid boost is powerful when turned all the way up and can take a bright spanky single coil and make it sound very thick.
the amp and signal chain someone uses will make a huge difference in how well the system works. i typically use an old '66 deluxe reverb these days, but for a while i was using a tweed deluxe clone, a heavily modded musicmaster bass, or a tweed bandmaster clone a fair amount as well. if your signal chain is guitar->cable->amp, then i think the system works amazing well. the more stuff you put inline, the less well it tends to work. clapton basically uses a tweed amp (was a twin, now i think bandmaster) with a wah, an occasional ts9, and a leslie. 90% of the time, its just the amp with every knob at 7. that lets you roll the volume down to get clean sounds, roll the volume up to get some good dirt, and use the boost to push things hard for full saturation. the mid boost does have a certain voice that some may not love, but it does its trick really well once you figure out how to use it. if you rely on pedals for your dirty tones, it works less well, and the input needs to be able to handle a very hot signal. my buddy runs his green strat into a jetter red shift (a gift i almost regret parting with lol) and maybe a trem or delay, but thats it. he uses either a blues jr, a rivera, or a custom made bf fendery type amp
