Nah, no point comparing coilovers to springs cause theres £600 -£800 difference in cost. Plus setting up costs...It would would be like comparing matched inlets to a set of cams, both gonna give you improvements but huge difference in how much it costs to get you it.
All depends on what you plan to use the car for, the type of driver you are and how deep are your pockets or balance on your credit card.
I've run H&R's for 5 months on cup shocks. Spring is hard and suited to track and probably european roads. It loves big sweeping bends but maybe a bit choppy for uk roads. I wasn't sure till when I went to 18's and now there are perfect. Coliovers are great but lets be honest....80% cars on them never see a track, only adjusted once (and most are set up badly) and wouldn't out perform a good street shock\spring set up for the road. Still the best compromise but only at the right money. I'm just keeping my eyes on 'for sale' section but ultimately still got lots to spend before going down that route.....
Eibachs are a superb progressive spring but weren't low enough for me. The clio needs a significant drop (cause they sit so high standard) and even though theres not much difference, 5-10mm in suspension terms is a lot....