From: core
I have experience with Technic, FTB/Forge, and Bukkit/Spigot. There are many philosophical issues with Technic which puts them out of the picture entirely at the moment. Forge is my favorite platform and community, so that's the likely target for the foreseeable future.
As you can see in the post you're replying to, we already have mods up and running. We're using the Infinity modpack using the FeedTheBeast/Forge platform. The reason this isn't a custom modpack (yet), is because that requires a lot of time and energy to plan and maintain with patches and updates to the constituent mods. The modded server is running 1.7.10, and is also already running some custom mods that I've written.
The only thing Technic really has going for it is the ease of use on both sides of the players and modpack managers, when I was helping run BusinessElite we tried moving over to FTB and it was major pain in the ass compared to Technic. There was only one guide for creating a custom FTB Modpack, and we ended up just giving on it due how much time it took just to put out an update. Seemed FTB only really cared for their own official modpacks. Yeah, Forges community is pretty nice. Have you had any experience with Cauldron? It's Forge+Spigot for Servers (Combines the Plugin Support from Bukkit, and Forge), the Cauldron community is also pretty friendly. Helped out the Developer multiple times with server issues we'd always run across. But I agree, Technic has it's issues which I can't really blame you for disliking, but one thing I did end up liking was it's ease of distribution and use.
If you haven't messed with Technic's Solder, it makes things kinda simple. It allows you to push out very small updates when needed and organize things. I know Technic's Devs and Admins are a pain, trust me BusinessElite lost everything due to a minor issue that could've easily been reverted by the Technic Team, but they chose just to ignore us.
Also, from experience most of the issues you're going to run across are server sided. Since 1.7 handles ID's you don't have to worry about ID conflicts anymore. Compatibility is the only thing that you'll end up having to deal with, which can easily be handled server-sided by banning/disabling the block entirely. Optimization will also end up being an issue, but that can easily be dubugged with Opis, and handled with Spigot.