The Nook is finally here. It turns out to be much less Kindle-killer than Kindle-clone, and a slow one at that.

Barnes & Noble Inc.’s (BKS) new electronic book reader, which goes on sale today, bears a striking resemblance to the Amazon.com Inc. (AMZN) device that ignited the e-reader market. It adds some useful features the Kindle doesn’t have, and many of those it lacks won’t be missed.

But the Nook falls short in one critical area: speed. In just about every important function—opening a book, turning pages, and especially starting up—it lags behind its competitor.

How slow is it on start-up? Achingly slow. Might-as-well- go-pour-yourself-a-cup-of-coffee slow. Maybe two cups.

Amazon’s current-model Kindle 2 takes about three seconds from the moment you release the power button until you can start reading. On the Nook, it takes a minute and 50 seconds.

Luckily, most users let an e-reader go to sleep rather than power it down, making the Nook’s pokiness less evident. Still, speed is a glaring issue—one that Barnes & Noble says it’s aware of, and promises to address in a software update early next year.