Solo zippered case
[Sorry for the way-too-long response, but hope it helps someone]
I've had this leather case for a couple of months and really like it. I first got it for use with my iPad2, although it now is the home for my shiny new iPad4.
http://solo.net/solo-vintage-padfolio-for-ipad
Prior to this I'd always thought of leather iPad cases as an overpriced luxury and preferred to stick with really cheap $10-15 synthetic foam cases that I'd just replace every few months.
Then I saw these on sale at my local Sams Club for $40 -- a price low enough to make me give it a shot. (I suffer from notorious cheapness

)
I must say that I really like this case a lot. At last I finally appreciate the value of leather, not in terms of fashion/appearance, but in how well it resists sweat/oil from constant contact with my hands as I carry it around throughout the workday.
One of the initial attractions of this case was that it had room for a small paper notepad on the interior flap. Since I haven't removed paper entirely from my day-to-day workflow, I thought this would be a nice feature. Well, I ended up removing the notepad within the first week and haven't missed it since.
Other things I like: The case has enough interior pockets and room for all sorts of stuff that I tend to carry with me. For instance, in mine I keep a stylus, my ID badge when I'm not wearing it, a (short) pen and mechanical pencil, a small screen cleaning cloth, business cards and an extra Lightning/USB cable (but not the power brick).
The iPad itself is held securely in place with a velcro-covered flap. There is zero chance of the iPad sliding out of the case accidentally. The easel feature (below) also uses a velcro strip to do what it does.
What I didn't like:
The interior flap has a small magnet that is supposed to work with the wake/sleep sensor on the iPad, but in reality I found it too small or weak to work effectively. However, one workaround is to take one of those flat, neodymium magnets (from inside of an old hard drive) and place it on the inside of the slit where the paper notepad would normally slide in, on the opposite side of the existing sewn-in magnet. This creates a stronger field that properly wakes/sleeps the iPad.
I'm also not absolutely sold on the way the case is designed to transform into an easel to prop up the iPad. It's also pretty difficult to use when you want to lay the iPad flat on a surface or on your lap to type. More often than not I find myself folding the entire case cover backwards on itself to use in a flat configuration.
What others may not like:
This is a pretty heavy case, both in bulk and overall additional weight. I haven't done any actual measurements, but I suspect it nearly doubles the weight of the iPad itself. When zippered, the case is around 4cm thick. Personally, I don't mind as it feels no different than carrying around an old-school leather-bound organizer. And even with the extra bulk, I like how much padding and protection the thick leather adds. And another thing: with the extra padding, it I rarely notice the excess heat that the iPad 3 & 4 is known to produce.
There's no opening for the rear camera. Not a big deal for me since I almost never use it, but may be a factor for some. All the other ports and switches are readily accessible.
Overall, not perfect but still the best case I've owned since my first iPad in April 2010.