Seany,
For what it's worth, here's my contribution. I currently play a 16 inch tunable.(Alberto Alfonso). My first drum was a very nice non-tunable 18 inch made by Alberta drum-builder Brendan Glass. For two years before I could afford that drum, I practised on pizza take-away boxes, telephone books, and a home-made practice pad made from cardboard glued onto a circle of plywood, with a cabinet handle on the other side. Inexpensive, but effective for practice purposes.

Benefits of a tunable, IMO (and here I mean a good, well-made tunable, not one of those cheap thin-skinned jobs with the steel rims and outside-the-shell tuning lugs):
1.It's tunable!- you can adjust the drum to the environment.
2. See #1.

Disadvantages of good, well-made tunables:
1. Can be expensive.
2.Can be heavy.
3. Tuning screws can be hard to see in dimly lit pubs - risk of poking allen key through skin, esp. after a few jars of the black stuff.

Here's one thing to consider, though - if you stick with bodhan playing, no matter which drum you opt for as your first, you will always want another one. That's a true fact. Same with tippers. There's always another one, that you don't have, but need.Good luck, and have fun.

Cheers, Bardford

BTW, a little thread creep here, but did I miss something? When did the bodhran become the Hran?