I'm not an instructor and I wouldn't put myself in either the PSIA or PMTS camp. I would say the PMTS presents itself as a systematic approach to learning to ski better while PSIA is more of an organization that presents tools that can presumably be used to teach skiing. Most ski schools are affiliated with PSIA. I've been working with PMTS materials and I think the approach is generally sound and the drills are very benificial. The only downside to the PMTS approach that I potentially see is that I'm not sure it doesn't deny some skills that can be useful in certain situations. Specifically, I think there are some situations in which rotary movements are useful tools. A lot of very good bump skiers, for example, advocate the use of rotary movements similar to what one would use when doing pivot slips. Indeed, pivot slips might be taught as a prerequisite for bump skiing. I think that PMTS advocates would say I'm wrong and perhaps I just don't understand the nuances of PMTS well enough to understand. I also have some "political" issues with PMTS. As an outsider my impression is that PMTS and its followers almost present themselves as a persecuted and misunderstood organization and you either believe in PMTS or your wrong. I also don't see, and again I may simply be niave, that PMTS is that different than what many folks outside of PSIA are teaching. For example, Eric and Rob DesLauriea (SP?) seem to present some of the same techniches and drills in their book. And the approach of Lito Tejada-Flores (whose books and tapes are excellent, IMO) is generally very consistent with PMTS and Harold Harb even demonstrates techniques in at least one of Lito's videos. All that said, I think Harb's books and videos are excellent instructional tools.