Schwalbe ZX or Conti GP4000

This might help if you're still stuck:

http://mccraw.co.uk/gp4000s-vs-ultremo-zx/

+1 on Vittoria, the open corsa is v good and easy to fit, IME

Also the Michelin option mentioned would serve you well, I only ever used pro 3's and they were FAST. Grippy in dry but not great durability. V cheap at the moment. If the pro 4's have improved durability over the 3's then they're a no brainer, as a cheaper summer option.

I must have got a lucky pair of ZX's. They're currently up to 3200 miles of North Yorkshire lanes and back roads and still look good for a few miles more. These are the green stripey ones and I haven't noticed any lack of grip - at least I haven't fallen off yet. And - the sidewalls are intact and undamaged.
In fact, I've just bought their successors for when I do need to change - another pair of ZX's at a great price from Spa. Probably because these are the pink stripey ones and were in danger of being left on the shelf.

I have both sets of tyres! The ZX look nice and roll nicely; but they do-not last very long. The Conti's are far more robust - roll nicely and last longer.

My dad uses zx's and rates them. Although he destroyed one first ride out. Sidewall slit with inner tubing bursting out. Nasty!

the open corsa cx are a race tyre, fastest rolling clincher available I believe. Grippy in wet and dry aswell.

Running conti for a year now, couple of issues.

They do puncher contrary to beliefs here, I've had 4 tyres this year alone!
I find they grip very well in corners although I'm still noob at fast turnings so..

I'm very interested in changing to victoria open cross ones but unsure how they compare for a race tyre?(also insure about moving to 25 from 23mm for racing) views? Is it noticeable?

I've always been fine on Ultremos (used them summer and winter for 4 years), for sure they do cut up but they're a racing tyre so if you use them for training (for the grip and low rolling resistance) then it's something you need to accept. Somehow I've managed to avoid any of the failures to (must have used 15-20 Ultremos over the years) but have seen first hand failures on mate's bikes so generally don't recommend them these days (happy to carry on using them myself).
I have used GP4000s and they're very nice but they don't grip quite as well as Ultremos (but you really have to be pushing it to notice any difference), they resist cuts better to (puncture resistance I'd say they're similar), it's likely the tyre I'd switch to if I gave up on Ultremos

Dont use the Schwables unless your using them on perfect roads. They split and puncture too easily. I have given up on them.

Can't comment on 4000s but the ZX is a great tyre, really fast, looks great and no punctures in over 1500 miles. Only problem is after about 750 miles, strands of material start peeling from the side wall, which at the time was a bit unnerving. Spoken to schwalbe who reassure this is not structual and tyres remain safe??????

I've tried Schwalbe, Michelin and Conti. Conti 4000s in the summer months is imo by far the best of the bunch, even if it's a bit dull. For what it's worth I love Schwalbe durano in the winter. The conti 4000s grips well, is fast and reasonably hard wearing. A great all rounder.

Pretty much my strategy too.

I've tried Schwalbe, Michelin and Conti. Conti 4000s in the summer months is imo by far the best of the bunch, even if it's a bit dull. For what it's worth I love Schwalbe durano in the winter. The conti 4000s grips well, is fast and reasonably hard wearing. A great all rounder.

Use Schwalbe ZX and although I love them, super grippy and fast, the sidewalls seem very prone to separating and cut up very badly. Saying that mine have proved to be very good value covering over 2000 miles or so.
Hope to fit Continental or Vittoria next time though

I will I will, raced the Pro4 Service Comps last weekend, and there were two sections of gravel 1.2km and 700m over a 145km course... they came through sweet as, no cuts, no punctures and feel very fast,
Also use the GP4000s for training great tyre.
Have used the ZX's also really good tyre but as mentioned do cut up a bit.
Haven't had the chance to try the Vittoria CX, but will be next on the list after the Pro 4's.

If you don't try the ZX you'll never know how they compare. Plain black are slightly grippier than the colours.

Oh, and no-one's mentioned Pro4 Service Course yet...
http://road.cc/content/review/82468-michelin-pro4-service-course

Lowest rolling resistance, 320 tpi , grippy in all conditions, like tubular but with clincher compatibility

Vitoria open corsa cx ! Amazing

I personally think ZX's look the business but have found they wear really quickly , plus prone to cuts and find they develop circumferential cracks. If you want a quick tire but don't mind replacing them every 1000 miles or so then they are worth a punt.
I've had gp4s on my commute bike for about 2000 miles, never had a puncture, cut or crack and they still look as though they have miles left in them!

my view is if u want quick tire and want to colour code your bike but don't mind replacing regularly then go for zx's but if you are on a budget and want to fit and forget then go for conti's

I have a set of the Conti gp4000s and gotta say I can't fault them

Slightly faster, a bit less grippy and not at all as durable as GP4000s.