f4 would be a lot more taxing on your eyepieces, and you'll need to invest in some premium eyepieces, or accept that the outer 1/3rd of your view will show seagulls eating chips.
Are you looking to do any imaging?
Also does the EQ5 have RA+DEC tracking motors? It might be worth getting the HEQ5 which can be upgraded with the SkyScan GOTO capability. It's also a more solid (heavier) mount which will be better for imaging too, should you go down that path.
I'm sure Mark Hodson will correct me on anything I said wrong