When 3e was announced, I was initially very wary, and for the first few months I was definitely anti-3e because I was so afraid WotC would mess everything up.
However, it became clear over time that 3e had a lot in common with the huge body of house-rules my game used. It was similar enough that if you went back today and played AD&D 2e with the body of house rules we used before the announcement of 3e then you'd think it was an attempt to retrofit AD&D with 3e rules. To us, 3e felt like the natural, logical progression of the game. 3.5 felt like the results of 3e being exposed to the crucible of mass-market use, with things like front-loaded rangers and ambiguously worded cleric domain abilities going out, with a few changes we didn't care for (Pokemounts ect.)
With 4e, it doesn't feel that way. The house-rules and variants we used (nowhere near as many as with 2e, as we are generally much happier with 3.5 than we were with 2e, but there were still some) weren't going in that direction. The big rules changes, and underlying philosophy changes are a radical shift in direction from the style of play we've been drifting towards since 2000. Adopting 4e wouldn't be to us like taking the next logical step in D&D, it would be like throwing out the gradual progression in design and play style that our group has had since long before I joined for a strange new game that is divergent in style and flavor.