Thunderheads are great heads. If you are wanting to stay with a head that uses replaceable blades, it is an excellent choice. Off the top of my head, I can think of a couple more that I would place in the same category with many heads of game to their credit using trad gear: any of the Muzzy products, Magnus Stingers, and Razorcaps (if you can take the high $$).
That said, get a pack of woodsmands, get a good file and a stone, watch Charlie Lamb's tutorial on sharpening them (in the how-to forum), and get to peeling steel. Bet you'll figure it out and never look back to replaceable blade heads. No shame in using them, but it adds another level of satisfaction when you take game with a head you've sharpened yourself.