I think the big question is are they really good at training you?
Not just if they give you up to date knowledge, but also, do they give in depth and useable knowledge. Practically oriented as well?
Still having doubts how effective such things can be, I really think most things have to be learned hands on with practice. One needs the manual dexterity for many things and no vid is gona give that.
Plus there is a lot of small little tips and tricks to effectively service locks, at least here many euro profile locks have their little trick how to dis-and reassemble them, not sure how it is in the US.
I would recommend maing friends with local lockies and building yourself up from there as well so that your knowledge won't get "theory-heavy"
Another question to consider are they worth their price?
I don't know, I never took them, I'm just playing the devil's advocate here
Did anyone took any of them and if yes what's the experience? Also will they go back for more courses?
Look around and research the topic well DennsiK before you commit, I heard they are rather pricey.