The duplexer is a user installable option on the 3100cn. You can add it any time.

The 5100cn has a built in duplexer and it is usually cheaper to buy a referb 5100 than a referb 3100 & duplexer. The duplexer for the 3100 is $300.

Refurb prices right now:
3100: $290
5100: $550

290 + 300 = 590 for 3100 with duplexer!

The 5100 is also much faster on color, and has a slightly lower per page cost.

Thanks. I read on either cnet or pcworld that the quality on the 3100 prints were better than the 5100. Do you know if this is true or not?

The black seem to be the same on both - I can't see any difference. The color on the 5100 seems to have a bit more gloss than the 3100. Neither are as good as a "Photo" ink jet printer. I can't really say witch one is better. They are both noticeably better than the other low cost color lasers I looked at (Samsung and Okidata).

I had a 3100 for a few weeks and sent it back because it had many problems. The 5100 has been working very well so far.

Thanks. I'll be printing mostly text with a few graphics. Not much on photos. Crisp, clear text is my number one priority with vector graphics being number 2. Also, paper handling is important as I'll be printing on a lot of card stock.

Any experience with cardstock?

Thanks again. I've been putting off this decision forever since I can't go and see a print sample but I really just have to bite the bullet and order already.

I had not used anything other than 20# paper. Don't have any card stock, so I cut up a file folder to 8 1/2 x 11 and loaded it into the MPF. Set to paper type to "Covers 1". Printed this web page duplexed prefectly! No feeeding problem or jam. There was a slight curl to the "paper" after printing.

I would expect there may be some jams with thick stock. I doubt any cheap laser would perform flawlessly.

The 5100cn would be best for printing large quantities of cardstock as it has the capability to print heavier paper types (cardstocks) from the trays instead of just the MPF like the 3100