Eco makes for a great first pen or Nth pen. You get a well-made piston filler and a relatively lower price with various colours as well as nib options. Plus with it's clear barrel you get to see the ink sloshing around.
With each TWSBI pen, you get a toolkit that allows you to easily disassemble and reassemble the pen for maintenance/cleaning.
Note: Eco Lilac is currently only available on pre-order basis.
TWSBI Eco Lilac (Special Edition)
Nib: Stainless Steel
Filling Mechanism: Piston Filler
Weight: Body - 13g; Cap - 8g