I bought the older style of this model several years ago (at Costco) because a rotary cutter is much more accurate - it doesn't push the paper the way swing arm cutters do.
I got the new one about a half year ago @ Costco, and absolutely LOVE it.
The rulers are MUCH more accurate I don't need to measure and mark my paper anymore!
The first week or so I was annoyed that it locked up, but I learned to hold the right side down with my right hand and pull the bar up with my left hand, and it pops out.
As padawala mentioned it gets easier to unlock with time.
I have a scoring blade in my older style cutter, so I just go back & forth between the 2 when making cards.
My SIL was very concerned about the noise it makes, as she does crafting VERY late (or early depending on your view)
She'll get up @ 3 am and be making cards! She was afraid of waking up the family.