DIN is arguably better, but the "sky is falling" reaction often presented in regard to the hazards of yoke valves is a massive overstatement of risk, at least in terms of diving in environments that do not include a hard overhead.
I have approx 1700 total dives, the majority of which were done with 1 or 2 yoke valves on board and I have yet to have a serious problem. The only issues are the ocassional (maybe once every 100-130 dives) occurrence of a very small leak from a bad o-ring that I should have checked and changed anyway. None of these occurences posed any threat to the safe and normal conmpletion of a dive.
I am slowly converting all 24 tanks that I own to DIN/K valves as DIN does make more sense and in hard overhead environments is arguably a neccessity due to the potential of valves/first stages getting banged around. DIN valves are generally a cleaner and less snag prone configuration in normal open water and soft overhead environments as well. Once all my tanks are converted, all the regs will be converted, but until then I am not worried about using yoke valves in soft overhead environments and am obviously not real concerned with getting the conversion process done tomorrow and will continue upgrading a few tanks every now and then.
Convertible DIN/K valves are about the only convenient option in some places due to the abscence in some shops of whips dedicated to DIN fills. It's an easy matter to install the insert and have your 2250 to 3300 psi tank filled as a regular yoke valved tank.
As for converting a reg to DIN, and then traveling to points where you need a yoke equipped reg, you have three options.
1) Convert it to DIN and then use a yoke adapter. The upside is convenience the downside is that it adds some lenght to the reg whihc can make it easier to hit it with your head.
2) Re-convert it back to a yoke configuration using the old parts. Simple and quick to do if you have access to a yoke nut socket and torque wrench, and to convert it back to DIN, a suitable sized allen socket. A bad idea however if you lack the proper tools but still do it yourself. I see people who have done this conversion with a large cresent wrench which creates the potential to undertorqe the retainer nut, potentially causing the nut to loosen and leak. Alternatively and sometimes subsequently, they crank on the retainer nut with the big cresent wrench and over torque it. These are also the folks that end up complaining about cracks in the first stage bodies and who then like to blame and bash the reg manufacturer for it.
3) buy another reg for traveling.
