If it is grid tied, you should not have any issues, as the GRID tied MUST maintain "grid" spec. power. generators and such (diesel especially) are cyclic based on "pistons" moving, so they are not as "tight" in tolerance...
You can always get a power conditioner to feed the generator power through.
I'm still on the fence as to what I want to buy. If I get a generator ($1700 for a Natural Gas Generator with transfer switch at Home Despot), I might send the power through a power conditioner. If I do a grid tied PV panel...then, no need, however I'd need to get enough battery power to supply my juice at night (in the case of a power outage).
I can see benefits to both and have yet to decide for myself which is better.
--Dan