Hmm... I collect both lines, and due to the affordability factor and my personal tastes, I go OT only on the Busts, but everything on the Bust-ups. If you went OT Bust-ups only, it'd be even cheaper, and easier to collect, and obviously playing catch up on those things is a piece of cake too, with or without the "chase" pieces. Another factor to consider is space. The Bust-ups are a lot smaller (though there's more of 'em), and are probably easier to display. A lot more variety with the Bust-ups too, and maybe a little more "fun" collecting them. They're cheap, and would likely be pretty easy to stay "complete", if you're into that at all.
Obviously the regular Busts are a higher end, more "mature", colletible. So if you want to go with something much nicer in quality and presentation, that might be the way to go. I guess the cost factor would depend on how many busts vs. Bust-ups were released in a given year. You can grab each series of Bust-ups (in peson) for about $30, easy (excluding chases). Each regular Bust would likely cost you $40-$50 shipped. If you'd rather avoid the headache of chasing stuff, just one or two busts a year might be the way to go.
Kind of a toss up really, Brian. I think it may really boil down to - do you want to have a lot of different characters in a smaller version, or just a few (fancier) characters in a larger size?
I'm a psycho completist, so my answer is biased in that if I was forced to choose one or the other (according to your all of the Bust-ups vs. just a couple Busts), I'd have to go with the Bust-ups so I could have the entire line of them, as opposed to just a couple regular busts.
Tough call though. Good luck...
