I don't know what is your experience with Linux, but I think it's very easy to work with this board.
If you don't need any particular customization you can download the Linux or Android image from the official site, burn on a SD card and nothing else more.
In order to get PD working you can install using one command line (sudo apt-get install puredata), or if you would like to run the special version for UDOO you can follow this post: http://www.udoo.org/pure-data-for-udoo/
UDOO is a great board since you have the power of four Raspberry and the flexibility of an Arduino Due.
Another great thing is that you have audio in and output already available without buying any external sound card.
So to answer your question: I think UDOO is a board usable for anyone has a little of interest in computer science or/and electronic. You have not to be a super geek in order to get things work on it, just have a little of experience with Ubuntu. Sometimes you will need a little of patience to follow some guides online to customize/install things that you need and are not already available.
If you don't need Arduino at all or you want to save some $, you maybe prefer to use a Raspberry, it's cheaper, it's very popular (so you can find a lot of documentation and support), but consider that if you want use it for synth you'll need an external audio card (since the integrated one has only output port and audio depth is 14bit) and if you use complex patches you will probably need of more CPU power... Anyway you can try... Raspberry costs about 25$, so I think it's worth a try!