Probably one of the biggest downs (imo) to working in trades is you will be around a lot of really stuffty people. There's plenty of good blokes but there are a lot of people that are just angry all the time over nothing, and after spending a lot of time with such people, you can become the same.
Though if you can stick through it then it's all G.
I can attest to that. I did vocational training in high school and grew up around a lot of tradesmen. They often come from low income backgrounds and are very jaded. A lot of them will forget up a lot being irresponsible with the amounts of money they earn which is far greater than anything they are used to. Getting into stuff like bitches, expensive purchases, drugs, etc.