I appreciate everyone's comments, very interesting thread. I'm not sure what you mean by "can take more power" I've had the opportunity to play my nl210 along side a thunder child and the TC wasn't able to go as loud. That was very apparent and clear cut.
The Baer seems to be a bigger louder box then the TC is that the case?
The NL210 is a nice box, and assuming you have the model I had, it is VERY goosed in the upper midrange (I liked that actually), and tight down low. Given the much more even voicing of the Thunderchild, versus the NL210, just like the AE210, which is similar but not as extreme in that midrange voicing, the impression is that it will be a bit louder in a solo setting when not pushed to its absolute limits. However, for the ability to handle strong peaks like slapping and digging in, and in the ability to push some real low end, even given its very small size, the Thunderchild is quite amazing, and will outperform most 210's across a wide range of frequencies.
The Baer cab is more efficient, since its performance at 8ohms is quite similar to the Thunderchild at 4ohms. The low end is about the same, as is the maximum volume, but the nature of the midrange response from 500hz up is quite different, and will appeal to different players.
That being said, while the reliability issues I had moved me away from the NL210 (which I assume have been taken care of in the updated model.. haven't really heard many reports on that model), it is one of the best sounding 210's I've owned, and will give the amazing Bergantino AE210 a run for its money if you like it 'tight and bright'.
Also, remember, there is no free lunch, and a cab like the Thunderchild (much less the Acme) takes more power than a typical 210 or 112 to get to full volume. If you tested your NL210 versus the Thunderchild with, for example, an EA Doubler or Micro, that head would not have the ability to push the Thunderchild to its full volume potential. And, with the master set at the same setting at moderate volumes, most cabs will seem louder than the Thunderchild. The difference happens when you have some real watts (i.e., around 500), and are really pushing the cab and digging in.
The beautiful thing about these full sounding, moderately efficient 12 loaded designs these days is that watts are cheap, and there are now some relatively high powered micro's that can push even the 8ohm versions to full performance.
Edit: Interestingly, the box that at one time defined this sort of 'super small box' thing was made by EA... the venerable VL110 three way cab. However, things have come a LONG way since then, and EA seemed to have changed their tonal vision from the original VL line, which IMO could hold a legitimate place in the history of bass cab development as the forerunner of a lot of this stuff 20+ years ago.