Stark differences, and the TLM-103 was the least impressive. The attenuation switch on the U87, when engaged, does (in my opinion) alter the sound of the microphone somewhat. Furthermore the TLM103’s ability to handle a higher sound pressure level (138db vs. 127db on the U87 … I couldn't bring myself to spend that kind of money a few years back (for a u87). 1. The TLM 103 I got because it's close to the u87, but costs a lot less. It has a transformer in it (all TLM mic's are transformerless though the U87 … But if the wa87 is in the same vein as the u87 (shootouts sound like it is) , and less "harsh" than the TLM 103 … I listened to the U87, the TLM-103 and the Mojave MA-201fet the day I got the U87, just on my voice. If you want to stay in the price range of the TLM 103, I A/B a Blue Blueberry against it and to me it was a more pleasing sounding mic for the following reasons. I got a second U87 right away …