As mentioned above, first you need to assess your needs! And then your budget
If size is a consideration, but expense is not, get an f/8 with multi-coating and a large image circle. The Nikkor f/8 is the best in this category, but my Schneider SA f/8, with only a 216mm image circle is a fine, very sharp lens. If you can live with the smaller coverage, then this or similar (Fuji, Rodenstock) are fine and will be cheaper. I do run out of coverage on my SA from time to time... But, I carry my lenses a long way. the 90mm SA f/8 is the largest lens I regularly carry.
If you need really small, you can go with a regular Angulon (which Ian mentioned above). However, the coverage with these leaves almost no room for movements. When I don't want to carry my 90mm because of size constraints, I take the f/6.3 100mm Wide-Field Ektar. It is close enough to 90mm, only slightly larger than the 90mm Angulon, and has enough extra coverage to make some movements possible. You might consider one of those if you are looking to minimize size and weight.
If you do architecturals or something else that takes lots of movements, you will need lots of coverage and a bigger lens. This means an f/5.6 90mm or even the Super Angulon XL (with 259mm circle, but a whopping 95mm filter size!). You can spend a lot for a little more coverage, so choose according to budget and real need here.
I have little problem with the f/8 versions focusing. Some, however, find the smaller maximum aperture dim and harder to focus. Try focusing one of your current lenses set at f/8 to see if you can live with the dimmer image for focusing. A good dark cloth and a Fresnel lens help a lot here. If you find you are not comfortable with the dimmer image, then it's back to a larger lens.
In the end, it's a compromise between size, coverage, brightness and cost (plus maybe whether you have filters already in a certain size).
Brand is less important. All the major brands are quality products and will yield excellent results.
Hope this helps some,
Doremus Scudder
www.DoremusScudder.com