I don't have an opinion about placing bolts because I've never done it, but from a user's perspective, in terms of keeping a low profile and having the least amount of metal visible to talkative non-climbers (including scramblers, abseilers, etc) I think the glue in machine bolts (requiring of a bolt plate) hide the best or if that's not suitable for the terrian then one of Neil's deeply recessed, camo rings. I'm also in favour of rings at belays where a rap off avoids descent gully erosion. Fixed hangers seem the most visible, and therefore the least appealing to me. However all that is just my opinion, and as I say, I've no experience with placing them.
You can read the pros and cons of bolt types over here:
http://www.safercliffs.org/code/bolt_guide.html
I should also add I'm against bolts anywhere near natural placement opportunities (with the exception of the aforementioned erosion reduction rap offs). Against "convenience only" bolts. Against bolted routes in trad only areas. Against new bolted routes too close to other routes. Against bolting anything that isn't worth leading a second time. Yeah, I know that last one is a big call, but that's my opinion for what it's worth.
Long live the bolt plate! |