Ask @CoolSquid what my initial reaction was when I first logged in to a server with Mekanism updated (something along the lines of "Oh my f**king god, what have they done to my machines)I have to agree with you...
All the item textures look stupid. The machines are no longer distinguishable (the red and blue tanks on the separator for example) and generally it doesn't fit in with the mod... especially an old mod which had a very well established style