[Poll: Spikes or Spikeless?]

Wear spikes most of the time now. I found modern pairs can be really comfortable - I have a pair of Nike Air Zoom Victory Tour 2 and they are as comfortable as my spikeless shoes, so I always stick to spikes for the extra traction.

[Urethane or not?]

I have been using Vice for a while as they always have good deals if you buy in bulk (I'm also based in the UK).

 

If you're not sure which is best for you, they also sell a variety pack for ~£20 so you can try a couple of each type before committing to buying one type in bulk.