I have had, for a couple of years now, a 1951 Raleigh Clubman that was re-painted a very nice, graphite or metallic grey color. This was done by a professional or a skilled hobbyist because the paint is very smooth and uniform. The bike has Bluemels alluminum fenders, an aluminum stem, and Raleigh steel all-rounder bars. The brakes are GB Sprite alloy sidepulls.
This bike came to me with blue vinyl pinstripes, which were nice, but I recently began fooling somewhat with reproduction decals. I did a waterslide seat tube decal on a 1960s Schwinn Racer that came out very nicely and was a great match for the original, thin graphics on the Schwinn.
So I figured I would try some new graphics on the Clubman. I ordered a couple sets from a bicycle graphic company in England. This included the Raleigh Clubman set, plus Heron transfers for the fork, and a Reynolds 531 transfer for the seat tube. I also got a "Made in England" transfer.
All of these transfers were of the "sticky" vinyl type and not the thin, waterslide type as I had with the Schwinn (the supplier of the Schwinn transfer was in the US and a totally different business).
These vinyl decals were not as easy to work with as I had hoped. The instructions say to wet the surface a bit, but wet versus dry did not make a huge difference as I experimented. Maybe I did not use enough water, but the decals were very sticky and really wanted to adhere to the surface.
After a fair bit of fooling around, and resorting to a couple of the backup decals I bought, I got a satisfactory result. These decals are heavier duty than the really cheap ones, though I will admit they don't have the subtle edge of a waterslide decals. They sit a little higher than the originals would. The colors are quite nice and they improve the bike.
My recommendation is that if you are going to do replacement decals or new decals, go for something that is similar to what you would have originally had on the bike, so that the sizes and shapes match. Don't go with a cheap decal set from the far east. Instead, stick with cycle-dedicated suppliers in the US or Britain. Don't be afraid of good quality waterslide decals - follow the directions and they mount pretty easily. With the vinyl decals, be very careful how you mount them and measure twice before trying to mount because they will want to really stick down once you stick them. You may want to buy back ups in case you mess up and have to fix something as well.