I've been using the Primus 2000 bottles and equipment for 36 years now. I did domestic and industrial heating and plumbing for over 15 years a long time ago (still keep my hand in now and then). Most heating engineers use these bottles (at least they did in my day).
You can get the Primus 2000 type bottles anywhere, though lately (last 15 years) I get the equivalent Calor 340 (340g) bottles. The Primus 2000 were blue when I first started. It is propane.
I am on my second neck tube as the first got worn out (at the regulator) with use. I use 2 different sized nozzles (15mm and 9mm ish), which will easily soft solder brass and copper tube up to 40mm dia. I also use it a lot for small electrical work such as shrink sleeving and larger terminals. The bottles are just the right diameter to easily hold and manipulate close up and at arms length. I am on my 3rd or 4th 15mm nozzle, as the metal at the tip burns away after a few years constant use. The system is great for surface work as it gives a nice steady flame. I've done quite a bit of silver soldering (non pipework) with the system, but it struggles with big stuff (I dunno, say 40mm cubes of steel). I bought the large Sievert pro system for that work.
This is all probably overkill if you have been used to a Ronson all your life. The price to get set up might put you off as well.
Steve