Our team built a 30 point climber, and it was the most successful robot we've had in a long time. We seeded fourth at our regional, almost exclusively due to our climber, and 13th in Archimedes (we weren't picked though).
Our strategy from the beginning was to shoot three in autonomous, full court shoot about 10 discs, and climb/dump. However, we had some problems. In both our events, our competition shooter performed significantly different from our practice one. At home, we could fire 10 out of 12 discs in the three point goal from full court in 40 seconds, including line up time, but we never made any full court shots at competition, only autonomous ones. We spent a LOT of time on our climber, and our climb time was 30 seconds to the top, which we bumped up to 18 seconds, then we broke our last spare worm wheel, and then went back to 30 seconds. Besides for this issue (we used 3 CIMS on a transmission designed for only 2, which is why it failed), our climber was mechanically perfect, and made it to the top every time it started.
If you're interested, here's a video of us climbing with the slow deployment mechanism.
http://www.youtube.com/watch?v=wL7eT4H2ARM
However, the climber had a fair share of disadvantages. The whole subsystem weighed about 30 pounds, and took a long time to perfect. We must have made 20 different iterations of the hooks before settling on the final one. It was expensive, as it used two five start (on the faster version 8 start) lead screws, which weren't cheap. Also, it was difficult to line up quickly, and our deployment mechanism at our first event was extremely slow. We used our shooter to dump the discs at the top, which was a poor strategy, as the depth of the goal in Archimedes varied by over 1/2", something we didn't think to test at home.
We also fell from the top of the tower, and really destroyed the robot. The frame of the robot above the wheels was destroyed and had multiple broken welds, so we ended up removing our shooter, hopper, and all the motors up there and replacing the structure of the robot with a spare one. We also built a new hopper. The scariest damage was the climber deployment lead screw, which had bent at a 90 degree angle, but through some miracle, we managed to bend it back and get it working again. Then, we found that our power distribution board was dead, so we had to rewire about 20 really inconveniently placed connections. Overall, this was NOT worth it!
With that said, climbing was a lot of fun, and if we had a little more time (and not lost a week to the snow storm!!!) we could have had a really awesome robot. Overall, the biggest problem with most climbers was reliability.
Our robot scored an average of about 60 points per match (with a potential of scoring 68 max with auto points). For fun, we trying cycling in a practice match (no driver practice with cycling!), and got 5 cycles with missing only 3 discs (but with no defense/climb).