The "interior" side has lots of gantries and overhangs to give it a more claustrophobic feel, almost like a mini - diorama.  I kept the sides pretty flat, so I could use this piece in between other terrain (Especially Space Hulk terrain).   This piece is pretty vertical, providing lots of places to stand without taking up a lot of table space- perfect terrain for the cramped quarters of an underhive or forge complex.
 

Here's a closeup of the detail on the horizontal tank.  Rivets and angles go a long way to establishing the gothic industrial look.  The rust washes are particularly effective here.  What's also amazing is the white "decals" in the upper right are actually stickers from a Zoids toy!  Once you flat coat them they look great.
 

You can see how claustrophobic the interior is in this shot.  It really feels like the depths of a hive or space hulk.   I'm really happy with this piece- the shapes, the colors, the playability- guess I need to start playing Necromunda again...  Be sure to check out its big brother, the Type II Filtration Tower!