Any advice on them. I hear it's the biggest selling wah of all time, yet all I can find in reviews is people complaining about tone-sucking and modding for bypass. If I can get one of these for about £20 ($34) is it worth my money? Will it need a mod to be in anyway decent, and is the mod easy to carry out? Also, what're other good wahs in the same sort of range? Thanks.
I had one briefly - paid some £70 for it new near 2 years ago. They are solid pedals - I had no problems with tone sucking and what-have-you - They do somewhat rely on you looking for it's kinda of sound though, but at least mine was quite responsive to different gain & distort levels. For £20, I'd say go for it, what can ya really get for a 20 these days, anyway?
The rig:
Gibson SG faded special -> Marshall MG 50/100 (working on a valve amp)
Backup: Vintage AV1
Newcastle United
There are different models of the crybaby over the years. The older 1s dont have an input buffer. But having or not having the buffer is debatable as there are plenty of DIY plans that call for input and output buffers w good effect. Stock they do leave some things to be desired but many of the mods are pretty cheap just the cost of resisters or capacitors. Not to say they suck completely stock, I used a stock 1 for years, they can just be better. Most expensive mod is putting a better inductor in em, next would be the cost of a bypass switch. At 34$ you got a good deal Ive paid that for broken ones.

Theres a thread on UG on modding wahs and plenty of sites on the net if you use google to show you what to change. You can add all sorts of pots and switches where it will do all sorts of things, but Ive found a few basic mods goes a long way.
The orginial CB is a standard these days. I own one, and use it quite a bit, espicially on solos. There are some cool intros I do with it. If you can get it cheap, I say its worth it. I love it, maybe you will too.
1981 Gibson Les Paul Custom (Black Beauty)
1980 Marshall JMP 2204