My main axe is a MH-417 and I love it. It was made in China which most guitarists frown upon but I haven't had any problems with it. The neck is very comfortable and the EMGs sound great. I've been gigging pretty regularly with it for the past 2 years in a Death Metal band and it hasn't given me any tuning or intonation issues thus far. I've even started incorporating softer parts in my songs and it sounds really nice through my amp's clean channel despite being marketed as a metal guitar. I'd definitely recommend it. It's a bit pricier than the Ibanez RGA7 that I had before but it plays and sounds way better.
As for the 6 string to 7 string learning curve; I played 5 string bass for about 7 years before I picked up a 7 string guitar so the move was a bit easier for me as I was already used to the low B. I found it helped a lot to simply extend whatever scales you may like to practice downward to incorporate the extra string. Finding ways to incorporate it into barre chords when playing clean or low-gain parts can add a lot of depth to your sound as well.