This really depends on what you want out of them and what you plan to do with them after your finished.
If you were to buy KW V1's which are approx £650 and keep these for 3 years.
You would have about the best street
coilovers that you can get and would last a life time.
If you wanted rid of these after the 3 years people would snap your arm off for these and due to the stainless steel construction they would look like new too.
Take the weitecs of about £450 if you don't wash these and wax oil these (which you wont) they will look very scabby after the same three years and resale value would have dropped to about £200 with less of a second hand market.
Buy £300
coilovers they'll be done after 3 years and you'll need new ones or won't be worth anything after this period.