It depends on your current level of brow training and budget, I'd have thought. Generally, my rule of thumb is if it's cheap and quick, you're not going to come away feeling confident, although it really depends on the individual trainer.
There are lots of threads discussing Microblade training, so use the search facility and have a good read whilst waiting for any more replies. You can never do too much research when it comes to sourcing training that's suited to your specific needs. Although, in the end, it can be a toss of the coin between 2 and you just have to go with your instinct.