Reading the arguments and the details it just seems like a lot of unprofessional BS on both ends. Yeah maybe the wood nerf was a bit much but that is just par for the course of Gregtech, making stuff arbitrarily more drawn out since its inception. But it is a config, just like any of the nerfs to IC2 recipes and other things. Just as it can be on, it can be turned off. In this case MDiyo took the first shot and directly made a change to effect GT's wood change. I can't say for sure if he was aware of GT's coding to crash when his mod is conflicted with I dunno. Though I'd wager just about any mod whose items are directly conflicted with would cause game issues. However the Pumpkin of Shame, despite sounding hilarious, and the crashing code was very childish as well. Honestly shame on both of the modders, it doesn't inspire a lot of faith in you.
If I had to personally chose between the two mods going forward I'd easily chose gregtech. Not because Tinker's Construct is a bad mod on the contrary I use it in my own modded minecraft folder. More because when it comes to the typical FTB set up, IE lots of machines that make the game too quick and easy by dropping extra everything in your lap, I really like how gregtech ties the mods together and puts effort back into the game. (At least for a while) It forces you to make machines and take routes you'd of likely never taken otherwise with many different mods. In that way I feel its a bigger boon to packs then TC's never breaking easy mode tools.
Though I'd rather not have to chose. Why can't the modders act like reasonable adults and we could have both?