Simply, the warmth, plastic boots have several layers and are quite a bit warmer. Most guide services do not want to deal with any frostbite problems while guiding. As a beginner/recreational climber...find a size that is snug...but comfortable. If you could not wear the shoes for one hour without discomfort....then the shoes are too tight.
I have been 5.10/11 since 1977. In my experience, a little bit of tightness may give you a slight advantage....you get up a 5.11a when normallly your limit is 5.10d...but I would much rather enjoy my recreation than climb at my ultimate limit.
RP's are a brand name for artificial chock stones. Like Stoppers, Rocks, Walnuts, Offsets, etc, it is the name given by the manufacturer; Pacific Crossing. Typically RP's were small to micro sized brass alloy nuts, similar to the Black Diamond copper/steel nut made today.
RP's were used, almost to the exclusion of any other micro nut, in Yosemite to push the frontier of what was possible with clean aid in the late '70s, '80s, and early '90s. With the huge growth of the sport of in the 1990's, many other companies began producing micro nuts similar to the RP.
Article Source: http://www.article-matrix.com
Victor Epand is an expert consultant for www.WarGear.info/. WarGear.info carries the best selection of military clothing, war gear, and combat accessories on the market.