In reply to Northern Climber:
Have used BD express, BD non-express, Camp wide bore titanium (forgotten the name, blue colour), Grivel Helix, Grivel 360 and russian..... jobbies.
Grivel helix are the best; quick to start, handle is excellent to keep them moving, but lack of movement in the hanger so can catch bumps in the ice. Rack very well with thier own kind....not so well with company.
BD express not quiet so good as helix to start and wind, but better at dealing with bumps. Social screws that will rack with anything. Non-express the same but slower.
Grivel 360's only used a few times, great once started, and in restricted positions, but a right pain to rack... to the point of needing to be complete 'loners'.
Camp wide bore titanium - don't laugh a good 'screw' if you've skilled! They're cheap and don't bite (and the teeth blunt quick). So whats good? Never use in virgin ice, pick somebody elses 'hole', and just rebore with using thier wider diameter, then they are surprisingly quick, but not as quick as the others above. Therefore great for popular belay points. Good for often climbed routes, saving dosh and weight. Absolutely crap if placing from scratch.
Russain jobbies.....say no more!!