Almost any portable amp will drive your Grados well, so the "best" choice depends on what features (especially source) you require and your budget.
The best way to get advise is to let us know which Grados you have and what your source is before anyone can help you pick an amp...
Yeah I am aware pretty much anything will drive them :) Just after something with good synergy.
I have the bushmills x Grado's.
I will be using primarily a Note 3 and a Laptop.
Open to USB Dac/Amp combos preferably that will either function as an android dac or atleast have a 3.5mm input as an alternative to using the dac function, so I may use as a DAC with laptop still.
My budget is flexible, if I can get something affordable that does the job then awesome, if I can get slightly better from a HiFi M8, then I am going to opt for the cheaper option.
Things I was considering are
e18 (when its available here)
e12 (already had and sold one of these a while ago :()
Open to suggetsions.