Shimano cable cutters are, IMO, vastly superior to the Park Tool ones. I personally don't rate Park stuff. That said, I think their heavy duty stuff is well made (truing stands/bike stands etc). I have found that their screwdrivers are made of cheese and cone wrenches and other hand tools just aren't tough enough.

Felco cutters are the best buy if you have the extra £. As with everything in the UK, stuff is vastly overpriced compared to that in the US and other countries. You may find some great deals online, as long as the overseas shipping is not too ridiculous.

I bought these Draper cutters and, for the price, I can't complain. I have cut numerous amounts of housing and inners for myself and friends, and they're still going strong.

http://www.amazon.co.uk/Draper-Expert-57768-Wire-Cutters/dp/B0001K9WXA