Hmm...
I've just skimmed this thread and there was a bit much to digest in one sitting, but I've got some Manchester cycling experience, Oxford cycling experience and just went to the Netherlands for a weekend... and all three of those have just come up for comment!
So... Manchester - daily commute. Cycle in to work is all on road, mostly with a cycle lane (on road). It's ok. It was daunting when I wasn't as confident on the roads. Surface sucks. Drains etc and large potholes/ruts etc are the norm (but I know where they are and avoid them).
Cycle home is mostly the other way, same thing, except by then Rusholme is up and buzzing and the cycle lane (which segregates the road from parking) is usually blocked at various points by busses/cars/taxis/who knows. No one is looking where they are going either. I can handle it now but it is certainly not for beginners! Alternate route - back streets and largely reduced traffic including some shared-use paths with no cars. Slightly longer, much pleasanter, except the surface sucks (in places) and it's not gritted in winter.
Oxford - Botley road here. Heading into town; there's either the bus lane (most of the way); when that stops there's a cycle path. There's also a cycle lane on the pavement; but the bus lane is more convenient and less bumpy, and less likely to contain stray pedestrians or cars reversing out of drives. Going the other way, there's not a bus lane all the way, but there is a pavement-bound cycle lane. At every junction, however, you have a yield painted on the path which presumably wants you to yield to things from both the road you're crossing and the one you're riding parallel to. Hellishly bumpy in places, and left hooking is a problem at at least two junctions. Normally not much traffic coming out from the side roads, unless you ride on the weekend, in which case some numpty is normally sitting in the line of the cycle path. Normally said numpty (this is Oxford) looks embarrassed and reverses backwards to let you past. Not gritted in winter.
Netherlands - we didn't do cycling in any major towns/cities but the inter-town links were perfectly segregated. Surfaces were great. When we ended up on-road, the rural backroads we were on were effectively one car lane wide even though they were not one-way; and both sides of the road had wide cycle paths. With no drains/ruts/etc in them either. Also, cycle routes were clearly marked and joined up. Again, not sure how this holds up in towns, but the UK paths often (say) jump you up onto the pavement, and then at the next junction suddenly vanish altogether with no information on where to go.
I think my preference is bus lanes. They're wide enough to avoid whatever might be lurking in them (even the horrible mess that is Oxford Road in Manchester near the station); and there is no other traffic in them aside from busses (or taxis). Cycle lanes are often in the gutter and sunken drains/grates/potholes/whatever abound, making half the thing unuseable. Unless you can do the Netherlands option and provide a cycle lane that's half the width of a car lane, with no drains/etc in the lane at all...
(edited for road misname!)