I'd recommend against one with a wrist brace. Instead get a Dankung style. Much easier to shoot accurately and much smaller. You grip Dankung style slingshots differently than you might first assume.

Newer shooters and those with very large hands might prefer a larger model, like one of these two (listed largest to smallest):

http://www.dankung.com/emart/large-general-dankung-slingshot-p-415.html

http://www.dankung.com/emart/polished-pocket-thunder-dankung-slingshot-ergonomic-p-434.html

As you gain experience, you may gravitate towards the smaller offerings, like these (listed largest to smallest, but all are smaller than the above two):

http://www.dankung.com/emart/general-stainless-steel-dankung-hunting-slingshot-ii-p-214.html

http://www.dankung.com/emart/polished-palm-thunderusa-p-620.html

http://www.dankung.com/emart/black-palm-thunderusa-p-342.html

The third one here is the same as the second one, just a polished finish vs. a textured finish.

I have many of these slingshots. The "Palm Thunder" is my favorite. It's small, but I like small. I no longer shoot my larger models very much. I have totally abandoned the wrist braced slingshots I have. They are less accurate, painful and tiring to shoot with the brace hitting your wrist, slow to deploy, and just cumbersome in general - especially the ones where you have to weave you hand into the brace by sticking it through a loop. The large diameter tubing choices available for wrist-bracers is limited, and there is no feel of finese in drawing the bands like you have with small diameter tubing on Dankungs or flatbands (as on the A+ slingshots someone else mentioned - I have some of those too, and A+ indeed makes "grade A+" slingshots).

You hold a Dankung style slingshot like in the picture below, with your thumb and index finger high on the forks and your pinky finger curled into the hole at the bottom of the grip (this hand position serves as your "brace"):

http://www.dankung.com/dk/images/XIE.JPG

The only wrist-braced slingshot I would consider geting now would be the "Saunders Falcon II" which uses flatbands instead of the large diameter tubes most wrist-bracers use, and you don't have to weave your hand into the brace - it just sits on top of your wrist automatically after grasping the handle.

http://www.sausa.com/product.php?id=3&category=16

Below is an example of a "weave your hand into the brace" type of slingshot:

http://www.barnettcrossbows.com/products/slingshots/black-widow

I find them to be very uncomfortable on the wrist. The ones where the brace attaches to the lower end of the handgrip require you to "weave". The ones where the brace attaches to the top of the grip (like the Saunders Falcon II) don't require the "weave" and are usually more comfortable. But I personally don't like either variation. No wrist-bracers for me anymore. They look high tech, but performance/comfort is lacking compared to more conventionly configured slingshots. The original "forked tree branch" slingshots used what is called a "hammer grip". You don't have your fingers up high on the forks like on a Dankung. Those are uncomfortable to shoot for me. the wrist-braced models attempted to improve on the hammer grip slingshots, and succeeded in that quest. But neither the hammer grip nor the wrist-braced works anywhere near as well as a "fingers high on the forks" style slingshot for me.