I personally dislike mechanical heads. I bought mechanicals once and after a few afternoons of shooting them I decided then and there that they are not for me. It once was an issue that some outfitters were banning use of mechanicals heads on their hunts. I'm not sure of this is still the case. But hearing that and then having my own issues with them sealed the deal for me.
I've been shooting Muzzy 3-blade 100g heads for years and have zero complaints about the performance of the head. I did shoot thunderheads at first but I didn't like how it needed a ring and then had to be screwed onto the shaft to keep the head together. Muzzy's lock in place with the tip and become one piece.