I always go for clear, dont know if this makes any difference for normal fishing, but I have found that a clear line and clear shock leader give better results when Bass fishing. coloured lines seem to spook them, but that may be due to the clear water conditions I fish in for Bass, Other species dont seem to matter
Reports say that Red Ice is almost invisable in water but not being a fish I cant confirm, coloured shock leaders are easier to see at night though, and some anglers say that coloured lines especially yellow are easier to see in daylight
only trial and error in your area can tell
Gray