Last time I used Ableton (2011), the recording cut off somewhere between 5 and 6 hours. From the email exchange I had with them, this was because they were using 32bit ints instead of 64bit ones. For a company that touts its partnership with Serato, and the ability of their program to work with Serato's DJ tools to specifically record DJ mixes (which can be many hours or even days long), this is absolutely unacceptab…
I've used Ableton but I found myself driven back to simpler tools that give a less digital sound. Also I sort of agree about the UI.