Audiokinesis Thunderchild TC112 and TC115-Which One is Better for Electric Bass?

Tone wise they're about the same. So it would depend on your volume needs and size/space preferences.

I'm not sure if the 15 is currently available in 4 ohms so that might factor in as well.
 
Pretty much what those two above said. Either will work very well for electric bass. I have a TC118 right now, and have used it for everything from bass (electric + upright) clear up through violin (and everything in between) with great success. You cannot go wrong with the ThunderChild line at all!
 
I've read many glowing reviews about both the TC112 and TC115. Is one better than the other for use with electric bass?

The latest generation (version 3) of these cabs is imo slightly better for electric bass than its predecessors, and of the two cabs, the Thunderchild 115 has a bit more "growly" going on when the mid switch is in the up position. That's because the TC115 uses a custom Kappalite-based woofer that has a bit of intentional upper-mid bumpage going on. When the mid switch is in the down position, that bumpage is smoothed away. The TC112 also has a mid switch, but its "growly" mode has less going on in that upper midrange region.

I'm not sure if the 15 is currently available in 4 ohms so that might factor in as well.

Actually version 3 of both cabs comes with a "4/8 ohm" switch... I put that in quotes because the actual difference is less than those numbers imply. Basically it's a 4 ohm, cab and you flip a switch and the cab can be treated as an 8-ohm cab so you can safely parallel it with another 8-ohm cab for loud gigs. I can explain the inner workings if needed, as I realize this is something that could be controversial at first glance.
 
Well, no real need for me to chime here other than to say all of Duke's cabs are phenomenal for electric bass, but there are different flavors of awesome. Thunderchild vs Hathor series. I prefer, not having had the chance to really play through a Hathor, the TC series. That's primarily because I want a more refined, smooth, sound vs the more traditional rock tone I think Duke has created with the Hathor series.

My understanding is that the TC115 will blown down a barn. I know from personal experience that the TC212 definitely will blow down a barn.