I've moved all my models over to it at this point. I was a bit wary of moving my larger, more expensive models over to it until I had put it through it's paces, but I didn't find any major problems with the gimbals or switches. When the Dx8 first came out there was a recall due to some oddly behaving gimbals, I believe. But this DX9 appears to be working just fine.
The voice alerts are a bit of a gimmick, but I've found using them for a minimum of items (timer reset, flight mode, timer alerts, etc.) they can be useful without being annoying. If I had telemetry on something I think it would be very cool to have it able to call out alerts on low voltage, over heat, etc. And if you're into planes there are probably other uses I haven't considered yet.
It has a rubberized menu roller which I really like. The DX7s has a mirrored type finish on it which can slip on the thumb sometimes.
Stick ends can be set pretty low, which I also liked.
Triple posiition switches except for the 2 two position switches at the top back corners. As I said, everything is assignable. If you have planes with retractable gear, flaps, etc, you can setup switches with sequenced output controls, very nice.
On the back grips there are two dial/slider type controls. They control whatever you want them to. But generally they are used to control AUX 3 and 4. Their resolution is not the best, but they would be useful for flaps perhaps, or controlling a turret on an apache model, or maybe controlling a couple of axes on a camera gimbal. I wouldn't use them for any precision flight surface or function, only rough control options.
It is a powerful transmitter in terms of features. More than I'm ever likely to use and as such I expect I will be using it until it stops working.
I'd recommend it in general. Compared to a DX8... tough call, especially with the recent price drops on them and the likelihood there will be some of them hitting the used market with people upgrading to DX9. You'll have to make your own bang for the buck determination on that score.