It would appear from the comments made here and from what i've seen on you tube, that the search for the holy grail of stoves goes on. The arguments for and against gas/meths will always be there. In a good many cases gas is quicker and more controllable, however, gas stoves are nearly always more expensive and normally louder. Two reasons for me to go down the meths road. The trangia design is a classic, otherwise it wouldn't have been around for so long. The problem i see with them is they are so slow to get up to temperature. With my own stove i have the choice of a fast boil time ( one pint of tap water, not room temeprature, to a rolling boil in 3 and a half minutes if required with 1 fluid ounce of meths), a boil time of around 6 minutes without the extra priming pan ( cut down tuna can ) and a burn time of around 12 to 13 minutes on one fluid ounce of meths. It cannot go wrong, no moving parts, it's light around 2 and a half - 3 ounces, including windscreen and at that weight i can afford to carry a spare just in case i tread on it. They easily fits inside my cookset along with my spork, cloths, sponge/scourer, pot grabber, washing up liquid, spare bowl and windshield. With the low fuel consumption one litre of meths will easily last me a week, allowing me to bring to a rolling boil around 5 five pints of water a day if i wanted to. As regards the cost, well mine cost me nothing, made from a cat food can, a cut down tuna can and a cut down lynx deoderant can with a little fibreglass matting and loft insulation i had lying around. It takes around 20 minutes to make and i have to say gives me more satisfaction when i'm out using it knowing i made it myself and it's all recycled materials.
Sorry almost forgot, as regards the o ring in the trangia, i never had a problem with it. If i have a simmer ring i have used that fully closed as a snuffer, failing that just the use the lid. If it's turned upside down and placed onto the stove for a split second that will put it out without damaging the o ring. I used a trangia, both military and civi for years without ever replacing or removing the o ring (not easy with cold fingers)