In case you're missing the implications in what Mark is saying, here's they are stated more plainly and less politely:

1. Variable speed pumps haven't been around long enough to be fully tested.
2. We don't know how the electronics stand up to thunderstorms.
3. Serviceable parts can be VERY expensive, and we don't know what the life expectancy is.
4. There's a lot of hype from ALL the companies about these pumps, and we haven't fully penetrated all of it, yet.
5. In particular, the savings compared to a 2 speed pump with proven technology generally seems to be exaggerated.