I love what this mod offers to bring to the game, but I found the 1.9 version to add some pretty hefty lag to the game. I had it installed with several other mods. I could not figure out what was causing the lag, End up removing all the mods I had and started adding them back a couple at time until I figured out which mod was adding the lag. This mod was definitely the culprit.
I may not have the beefiest of computers but I have been playing minecraft for a couple of years now and with mods off and on during that time...and have never experienced lag like this before.
For me the game would load I would see only sky and the sun after initial load. The game would sit like that for about 2-3 minutes then finally load all other graphics so I could finally move about. I would begin harvesting blocks they would pop out, and then reset. It would take a couple of minutes before the block update actually realized that I harvested the block.
After removing this mod and re-installing all other mods I wanted it everything was back to normal.