No catch. It's the most liberating experience so far for me since I started the vaping journey. I wasted tons of cash trying to find my ADV. With DIY I got to try a lot of different flavour profiles that I would not have taken a chance on buying commercial juices in the fear of wasting money.
The learning curve really is obsolete nowadays as there are tons of really good recipes available that others have already done the ground work on. DIYORDIE is a good starting point for tried and tested good recipes. Also check out Alltheflavours, very useful tool and many great recipes.
I agree.
If you look at the recipes from the resources @Andre posted, obviously use initiative and read comments where applicable, its difficult to go wrong nowadays. Great recipes were hard to find even just a year ago. Now there's plenty of amazing stuff to be found.
Of coarse you will find you don't like some maybe even popular recipes, but the same applies to buying commercial juice.
So there's plenty "weeding out" recipes you don't like.
The real beauty of DIY for me for example, the profiles I have vaped this week alone you wont find commercially. Because they are unusual, the juice maker would be taking a risk putting stuff out like this. I've been vaping Earl Grey Tea or Coconut Brandy for example - strange but awesome, but probably wouldn't sell well.