They're not as bad as people make them out if adjusted correctly. In fact, they're just as good as typical sidepul caliper found on 70s road bikes on chrome rims. And that's the problem - chrome rims, work fine in the dry, not so good in the wet.
It is essential to ensure they are set up so that both pads hit the rim at the same time (this is not guaranteed, bend things to suit) and that both pads contact the rim fully, not have half of it out past the rim. A good true rim with no flat spots is essential, more so than with caliper brakes, clean off any rust or it will tear the pads in shreds. A drop of engine oil on all the pivots and the sliders on the forks on a regular basis to keep everything working smoothly with minimal effort. Also be aware that there are two different types of pads - Raleigh and Phillips and they are not interchangeable. It can be time consuming setting up rod brakes but once done, you will probably never need to touch them for another 30 years.
If you are tall enough to straddle a 28" wheeled frame, they really do provide a unique riding experience. I wouldn't like to ride one in busy city traffic on a regular basis as they aren't very maneuverable but if you have easy access to quiet country roads, a 28" wheeled roadster is a joy. It might take a bit of effort to spin such a heavy wheel up to speed but once you do, the big wheels just glide along with minimal effort and laugh at poor road surfaces (remember the design of these pre-dates tarmac roads). IMO, a 28" wheeled roadster needs a Sturmey to make it pleasant to ride.
26" wheels are probably more common. Much the same applies but there is such a thing as a "light" or "sports" roadster with lighter weight tubing (check the diameter of the seatpost. 1" was standard, anything thicker suggests lighter tubing) and more sporting geometry. Most of these had cable brakes but there were a few like Elswick, Humber and Royal Enfield who produced sports roadsters with rod brakes. These bikes are a lot faster and easier to ride than most realise and single speed with a 60 - 70" gear would be fine for anything other than very steep terrain.
Also be aware that the quality standards within the British bike industry started to fall from the late 1950s onwards. Older bikes will often have better chrome and paintwork. Beware of Raleighs (and other Raleigh Nottingham built bikes like later Rudges, Humbers, BSAs etc) showing a lot of BB or headset wear as they are non standard threading.
