For me, RTW is an easy question-Alden. I chose Alden because of the Modified Last. That last is the most comfortable last and shoes made on it obviate the need for me to add an orthotic. The extended heel stay and Thomas heel provide all the support I need for the main arch and I just add a small cookie for the metatarsal arch. The banana shape is perfect for my foot and the narrow heel combined with widened forefoot mean I get a snug stable seating for my arch, with plenty of room for the rest of my foot. And it is made in a wide spectrum of fittings, so I can get the narrow heel width I need. In short, it is a perfect RTW last. Of course, there are plenty of Northampton makers who can improve on the build quality and the design choices are limited (primarily derbies), but nothing is more important than fit.
On the bespoke side, I am happy with Foster, primarily because of the good fit and design sense (I have three pairs). I will say, that there is room to improve on the quality side, and by that I am only speaking of the attention to fineness of stitching and other cosmetic things like heel detailing. I have shoes made by two other firms, each of whom used English outworkers, and in both cases, the workmanship was finer than Foster's (the only one I know by name is a Scandinavian working in the UK, who I am told is one of the best out workers ). From work that I have seen, both Lobb Paris and Delos may be the best in terms of the combination of design, workmanship and reported fit, but I haven't used them myself.