If you are used to a sealed 10 cab, your comments make much sense. One of the things that kind of bums me out about this site over the last couple years is the core of TBers who mistake 'good specs on paper' for 'better tone' in an absolute sense. There are always trade-offs in any design of speaker cab.
I personally love my TC112 and 115, but I also still have my Berg AE210 around for those times when I want punch, definition and a bit of grind versus 'big, wide, extended and polite'. Both have their place in the market, and both 'executions' can sound fabulous, depending on a player's needs and tone goals.
Also, +1 that I MUCH prefer to find a rig that sounds good right out of the box for what I am trying to do, and matched with the bass and heads that I own, versus going through a bunch of hi pass, massive EQ drama.
So, +1 that there is a far distance between the Thunderchild TC115 and the Berg NV610. I think those bracket the category of bass backline cabs, and both are completely top of the heap, and IMO 'best in class'.
Edit: I'm curious to hear what RColie (Bob) thinks of the tone of the TH500/TC115 'out in the room' if he shows up on Friday. The TH500 is pretty big down low, and a bit polite up top (in a different way than the TC115). I typically use my much punchier, tighter F500 with the TC115/112 and a J bass, to get a bit better balance of the lows to upper mids and treble. Not sure if I'm going to get that with the TH500/TC115 pairing, but it sounds DARN good with the A-C 70's J at home, so I am giving it a shot. I typically use my P with that rig, and the J with the Glockenklang/AE212, and both sound wonderful. Doing a little 'mix and match' experimenting this weekend. Might be great, might be 'meh'. Only one way to find out!