i got a Thunder and a Spektra Edge.
I have to say i like both... The Thunder hits like a hammer. Which is good for bold lines and always have good results with lining on difficult skin areas. E.g. Ribs...
It is good for coloring as well, but because of the stroke and the powerful Motor it's hard to use for soft shadings. It will work definitely, but in my opinion this ist the strength of the Edge-X.

I used the Edge-X for 2 times now. Sur you have to find your own setup with stroke, Voltage, Give... But, man i mentioned during the 2nd tattoo that this machine will be my daily drawer!
I haven't tried coloring yet, but if you look at John Dame's Vid's on Youtube i'm sure my Thunder will have have a longer rest.
With the longest stroke an no give, compared to the thunder, i feel that the edge has a bit more vibrations, but believe me... this is just at a point when you can find no other bad things about a tattoo machine...

And for the disposable grips, i used the Ego's which fit for the Cheyenne Vice and the Standard vie a few times. Also Easy to use and sure a good option, but for me i stick with the original Cheyenne Grips.
I Like the depth adjusting very much and also the way to lock plastic in to metal. Plastic in to plastic feels a bit weird.

These are just my personal feelings...
I'm sure there are some other opinions as well