I am trying to bring my training up to a new level but do not know much about powermeters. A cycling coach advised me to get one but have delayed doing so plus I am not a very technical person. Does anyone have experience with the newer Powertap models like the SL vs the SRM? Is the SRM really worth the extra money? Are any of them really user friendly? It would be nice to primarily use it for on the road and maybe have a set up for the track too!