Started in august 2005 and playing on both.
Right now I spend a lot of time at 1.29. I like the atmosphere and community going on mixed with shitload of nostalgia. Players know players, you have a very mixed community but can still play with people who doesn't understand a word of what you write. Another plus side - ages of the players. Most of the players at these servers are playing because of the nostalgia, which mean they've been playing a while. So far I haven't met a single player below the age of 20 (that I know of). People are just friendly and having fun together contra 2.0 where a majority are assholes and wouldn't go near you unless it was to scam you or kill you.
Just as mentioned - 2.40 got way more to offer gamewise and of course there's awesome people here too - but they are harder to find. At 1.29 you're stuck with the same equips, classes, monsters and known bugs. Don't expect it to be anything else but what it is. At 2.40 you get an update every week or so.