It can be easier to focus on the ground glass because it will be brighter. However, especially with some older designs, you'll want to double check at the stopped down aperture because some designs will exhibit a focus shift at different apertures.

Generally speaking, amongst the modern lens designs, it's nicer to get the faster wide angles like the 90/4.5 Grandagon in favor over the 90/6.8 because it will be easier to focus (and it also has more coverage but that is another design issue). But speed/brightness comes at the penalty of size, weight, and expense. But they are really nice lenses (no focus shift either)!

One of the frustrating things about the fast normal and portrait lenses is that the shutters they are mounted in do not have very high speeds. You can get 1/1000th (well more like 1/600th) out of a RB or Speed Graphic's focal plane shutter but if you are using the Aero-Ektar at f/2.5 for the short depth of field effect, it's hard not to overexpose outdoors in the daytime. Acme #5 shutters only go to 1/60th, Copal 3s to 1/125th, etc. Even the old Compurs with the Xenotars - hard to get faster than 1/250th in use.