I've bought myself a trangia , but I've never used one before , is it as simple as setting it up , filling the burner with metho and away I go ?
IMO, no stove is "simple".
My standard recommendation is to make tea on your new stove once a day for a month, no matter what the weather is like.
IME, there is no substitute for experience to learn how the stove reacts to wind and cold. And, one needs to become familiar with how stove reacts so that it becomes second nature and you avoid "gotchas".
Couple of things I've observed with the Trangia. I'll try to post some pictures to illuminate later this week.
WINDSCREENS - As others have mentioned, with any alcohol stove, you must have your windscreen system sorted. These stoves are not pressurized so the flames are very susceptible to being blown about. Windscreens must work with the stand and pot. The Trangia burner is sold by Trangia either alone or with a wide variety of stands and/or windscreens set ups. Some are great (but heavy) and the lighter ones are awful and offer horrible performance. If you have a bare burner and no windscreen or if you have the Westwind stand or the No 25 mini, you might just replace with a Clickstand and be done with it.
STANDS AND HEADSPACE - The trangia burner produces the best boil times with the pot a certain distance above the burner. This depends on the windscreen and other factors, but usually around 1.25 inches or 30mm. At this point, I pretty much only use my Trangia burner for cooking for 3 or 4 people with a 2 qt pot, so I like a bigger more stable stand. I currently use the Mojo Stand (google search) and a re-purposed MRS aluminum windscreen cut down to size. If I had to replace it (no need) I would consider the Clickstand.
COLD GROUND AND PRIMING - Like the Svea 123 or other Optimus white gas stoves, alcohol stoves require priming to vaporize the fuel. Putting them directly on cold ground or snow sucks the heat out of the stove and will produce horrible cook times. I carry a thin disk of very thin plywood that I use as a base in cold or snowy conditions.
OVER HEATING & SAFETY - Like the Svea 123, if you over heat an alcohol stove bad things happen. While they won't go !BANG!, they can boil over, spilling burning fuel on the ground. For this reason, they aren't the best bet for use in a dry forest fire type environment (unless you clear the burn area well) and if you use them on a wooden surface like a picnic table, you run the risk of charring it (done it many times). Knowing how to give just enough wind protection but not too much is key, hence the need for experience.
WEIGHT AND DURABILITY - The Trangia is very durable but a bit heavy. They do offer a bit of control - a lot more than most other alcohol stoves. Leghog's idea of making your own is one way to get a lighter burner, particularly if you primarily use your stove for boiling water. I'm lazy and just buy my UL stoves from Batchstovez. I have both the 1.0 and 2.0FE and just love them. Super light. Very efficient. Very durable. Great for 1 or 2 people. No simmer of any sort though.
USABILITY - The trick to controlling or dousing the Trangia requires putting the snuff/simmer ring on. If you toss and pray, you might miss. If the stove is overheated, this might also cause a boil over and flare up fire. I made a magnetic rod to put the simmer ring on reliably without burning my fingers. I consider it essential for using the Trangia.
One thing I love about all alcohol stoves is how quiet they are and how hands off they are. Basically, I light them and do other things with little fear of major problems. When I see steam, I return to the stove. But they definitely require practice and getting the system sorted out.
FUEL - Lastly, whether or not they make sense depends on the availability of fuel. This varies widely so it's very hard to make a recommendation on that front.