"DeusEx"

[m_c]

The main benefit of Gecko's is the microstep to full step morphing, plus they're small!

I've got 2 G251s in my lathe, and can't fault them.
I did think about getting the G540, but it wouldn't of fitted in the control housing, and I already had the SmoothStepper and C23 break out board so didn't really need any of the additional features of the G540. If I was to start from scratch, I probably would go for the G540, as it does most things you need (inputs/outputs/0-10V speed control) in one plug and play package. Just add power, a parallel cable, some steppers and resistors, and you're good to go.
If you do still consider the G540, look at the GC-02 and GC-04 connectors from www.homanndesigns.com, as they make wiring even simpler!
Also, the Gecko customer appreciation sale must be about due, so if you're not in any hurry, keep an eye out to get the drives even cheaper than what the UK importer charges