I bought them, mostly because it is very difficult for me to use an amp to practice.   They are definitely a good option - they work pretty much as advertised.  I run the app through my ipad and can get plenty of good tones.  They aren't cheap, but in the end I don't mind the price (I found them on a bit of a discount).  So I would say they are worth it if you are going to use them a lot.   Build quality is fine (I have Marshall headphones that seem a little better quality wise; a bit surprising given Boss stuff is usually pretty high quality - they aren't "cheap" feeling, but given the price...).   Other option would be something like a Fender mustang micro.  Not the same experience, no wireless, but would probably be better if you just want to use once in a while.  If you will be practicing regularly with headphones, then I would be tempted to try the waza headphones.