I've been playing on a small private linux server with some friends using the 1.03 version of this pack. We also manage the server directly, so I know we haven't changed much from the default pack (besides re-enabling biomes o plenty, but using the vanilla worldgen with bop included).
We've had a number of issues. One I think you know about, where during worldgen rarely the world will spontaneously crash the server with an exception while ticking a block, Ie:
Code:
2014-03-25 04:36:56 [INFO] [STDERR] net.minecraft.util.ReportedException: Exception while ticking a block
2014-03-25 04:36:56 [INFO] [STDERR] at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:663)
2014-03-25 04:36:56 [INFO] [STDERR] at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:276)
2014-03-25 04:36:56 [INFO] [STDERR] at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:587)
2014-03-25 04:36:56 [INFO] [STDERR] at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:484)
2014-03-25 04:36:56 [INFO] [STDERR] at net.minecraft.server.ThreadMinecraftServer.run(SourceFile:583)
2014-03-25 04:36:56 [INFO] [STDERR] Caused by: java.lang.StackOverflowError
2014-03-25 04:36:56 [INFO] [STDERR] at java.util.AbstractCollection.toArray(AbstractCollection.java:136)
2014-03-25 04:36:56 [INFO] [STDERR] at java.util.ArrayList.addAll(ArrayList.java:530)
2014-03-25 04:36:56 [INFO] [STDERR] at net.minecraft.world.Explosion.func_77278_a(Unknown Source)
2014-03-25 04:36:56 [INFO] [STDERR] at net.minecraft.world.WorldServer.func_72885_a(WorldServer.java:997)
2014-03-25 04:36:56 [INFO] [STDERR] at net.minecraft.world.World.func_72876_a(World.java:2716)
2014-03-25 04:36:56 [INFO] [STDERR] at glenn.gasesframework.BlockGas.onFire(BlockGas.java:332)
2014-03-25 04:36:56 [INFO] [STDERR] at glenn.gasesframework.BlockGas.onBlockExploded(BlockGas.java:926)
Etc etc looping for a long while.
Another is that block id 950, used by metallurgy ender ore types, with all its variable damage types like .9 and .11, show up as purple and black ingame. Isn't discoverable in NEI, and breaks instantly when smacked. We've also had instances where we've found bronze or iron brick blocks in the place of ores. I believe the server owner reports finding end stone in the nether, on occasion.. Weird stuff.
We've also had a severe TPS issue, even with only two people on and barely any contraptions or structures, that's only gotten worse with the passage of time. We thought it was zombie awareness but as it turns out, we tried running the pack without it and not only was the modpack suddenly pretty easy but the tps issues persisted.There seems to be no debug text about it besides the server not being able to keep up. We're really not sure what's causing it and it's making the game pretty unplayable. The server resources are not maxed out.
Finally, not really a bug I guess but invader miners have been kind of derpy and tunneling all over the place haphazardly and not really accomplishing too much. One did manage to breach the surface around a fort I built, and I guess while I was offline some coal dust floated up underneath it and was ignited, as I found a large hole where part of my fort used to be. Score one for the zombies?
I'd also like to mention that the hats mod seems to function just fine and is a silly addition to an otherwise inhospitable experience. (All of the above issues happened before we tried that mod, btw, so it's not the cause.)
Edit: we work/live together ingame and there aren't any people spread out. The Tps issue used to be mostly during the night, but we recently started moving a few chunks over to a vanilla forest/swamp/plains three-way biome (Because all the crops are coded to use vanilla biomes and a 'forest' seed will not grow well at all in a 'spruce forest' for instance.) This was triggered by us finally discovering a tier of metal that mattocks could be made of. Before we were just defending a pre-existing npc village and trying not to get the farmland trampled/blown up while we went crazy with watering cans and hiding underneath a small group of turrets and a lost soul plus an obsidian golem or two.
Now the TPS issue isn't isolated to night, but is only the worst at night, causing nights and any tasks to last nearly four times longer. It's a little better at day, but not by a ton. Really no idea what's causing it.