I bought this to pair up with my older heavily modified Epibird, refinished it and did the same mods (new machine heads, brass nut, EMG TBHZ pickups and no pickguard). The thing is that as no matter how much I love Thunderbirds, they are far from flawless. The bridge can be a bitch to adjust and to play at all, so im looking to upgrade those to Hipshots in the future. The tuning keys on my first one became bad really quickly and I think the original pickups are a bit limited, so in other words, mine become work projects for a while before it becomes playable as i like it. But thats just my personal preferences. The neck is also very weak by the headstock, my old one cracked halfway off and needed a gluejob. It now seems more sturdy then ever!
If you want a standard Thunderbird for a fair price, go for it! They look, sound and play great for those who are into them, its no a very versatile bass. I dont think they are as neckheavy or "clumsy" as many put it, although thats just my opinion. But its far from a flawless instrument.