1. It is a gel pen.
2. Both gel ink cartridges are 0.5mm.
3. The Pentel Energel is known for writing as smoothly as any other gel pen on the market.
That short list leaves out great barrel design and comfort, plus I haven't even mentioned the pencil yet. So needless to say I had pretty high expectations for this pen, and fortunately it lived up to them.
If you have ever used a Pentel Energel - the needle tip version in this case - then you have a pretty good idea of what you are going to get from this pen, with the added twist of the multiple cartridges. And twist it does. The top half of the pen rotates from station to station depending on what cartridge you want to use, as opposed to having a click mechanism. The barrel design is nearly identical in form and function to the Pentel Hybrid Technica I reviewed earlier this year. I raved about the barrel then (that was the only good part actually), so I am glad Pentel has put that design to good use.
At $7.50 a pop from JetPens, the Pentel Energel Multi-Function Pen is right on the border of cost/value for a multi pen in my book, but this one has been worth it so far.