Going with 128 GB. As of now, Ipad is going to be used strictly as a controller. I take lessons with an Ableton certified instructor and a controller guru named Jimmy Allison out of TX ( I live in NYC) and he was the one who mentioned buying new Ipad Air before Pro was even announced because he feels there are great music apps and a specific controller he loves which I think was called "Touchable" but I may be wrong. I do not plan to carry it around so I like the bigger display. I am sure I will get 5 years out of unit and may need more then the 27 GB on smaller model. I just purchased a new Imac after 7 years with my 2009 Imac which I am using right now to post. Other machine is strictly music production. My Iphone 4s lasted a few years because I went from 4s to 6 plus. For the extra $150 minus 10% because I am a vet, $135 is worth the money going from 32 to 128 GB.
FYI....I have received a number of PMs asking me for Jimmy's info. I do NOT make a penny by posting this and just want members who were struggling like me the chance to learn Ableton if all other methods failed. I tried Youtube videos, MacProVideo, Warp Academy, Groove3, and although I did learn by watching these tutorials, I learned more in 3 weeks of lessons then 5 months with videos One of the guys who PM'd me said he finally quit after buying Live 9 suite & Push. That sucks because had he took lessons, my guess is he would have stuck around. The decision to not take lessons changed his destiny. He already dropped over a grand so why not spend a little money on education.
http://www.austinabletontutor.com Tell him BobbyD from NYC sent you his way. All lessons use Adobe Connect with video conferencing and screen sharing software so Jimmy watches what you are doing. He records the lessons and sends them to you so you can view video and entire lesson at later time and move as quickly as you want during lesson. Plus he is much less than other certified instructors and can actually "teach" because not all people can use their knowledge to teach others. If you live in Austin, he runs the Ableton Users Group. Drop in and say hello. Plus he is one super cool, nice, hip, good energy person and you will enjoy working with him.