sure, they still alive but why would you use them? buildcraft and railcraft replaced by extra utilities. factorization seem to not have a porpuse anymore and forestry was mowned by minefactory reloaded..
Buildcraft is kind of neat honestly. Add in logistics pipes and you have a really cool factory feel. Items zipping around the pipes make things kind of like those videos in the 50's with the booming voice over a film of factory floors with workers pounding away... "INDUSTRY!!!! AND TECHNOLOGY!!! These are the innovations..." That kind of thing.
Extra utilities is interesting and I find myself looking for different applications of it but I really don't like the transfer system. As for quarries... yes the ender quarry is less laggy but I honestly like the bc one better. The BC one at least you know where you've mined without having to put out extra markers. It doesn't take a 1000 ender pearls (exaggerating I know) to make. A few diamonds, a bit of gold, iron redstone... boom in like flint. That having been said early game I go straight for a computercraft quarry anyways but that's me. The ender quarry's upgrades remind me a super expensive quarry +. The pump can be nice a way for pumping the nether but I still, despite the lag (which honestly I think could be fixed...) like the pump extending down into the lava and filling the tank as the redstone engines pump away. The feel of it is less... alien tech and more industry which honestly is what I look for aesthetically in my mods anyways. It's why I like immersive engineering and flax's steamworks so much.
Factorization is, imo, one of the most under appreciated mods in the DW20 pack. The ore trippling mechanic is pretty material intensive so not early game. But it is very fun to make a whole building for it and automate it. I realize this goes against the mentality that seems to be rushing through of smaller more compact machines that do multiple things. Honestly even the mekanism 5x is a huge ordeal to setup. Anything past double and all you're really doing is increasing ore production for your entertainment. The little cable moving thing, which I don't use and why I don't know what it's called, is pretty neat. I've seen some people make some interesting logistical builds using it.
MFR, IMO, doesn't work as smoothly as forestry. The forestry farms and other machines were scrapped in favor of MFR for most people because it's easier. Honestly you can always get easier and easier. You could just play creative. MFR machines offer no creativity or customization in setting them up and honestly I haven't seen any build using them wasn't your standard multi or single plot farm planter/harvester or mob grinder spawner. The other MFR blocks are rarely used. The biofuel thing is more of novelty than really effective compared to other more compact alternatives. I know there's prob effective builds but most people don't bother with it. The breeder/chronotyper/slaughterhouse or grinder is one of the laggiest setups I've experienced. The rancher is pretty useful for ink farms but just as fast as the old vanilla farm. now as I get more and more into the mod blocks I realize that for the most part... people only really use the harvester/planter and deep storage unit. Yes some go a step further and use the laser miner and spawner/grinder but for the most part I see people moving away from that and going towards other mods and alternatives. Honestly if there was a deep storage alternative I wonder how many people would even use mfr anymore.
I guess what I'm saying is I don't think forestry was "owned" by MFR. I think MFR flipped the easy mode switch and I question if it isn't responsible for some of the increased lag I see on some of the servers I play on. But hey I try not to use MFR if I can help it. I'm one those Deep storage and only because there's no alternative I can see.
