Reddit mentions of Pentel Twist-Erase III Automatic Pencil with 2 Eraser Refills, 0.9mm, Assorted Barrels, 2 Pack (QE519BP2-K6)

I would consider the pentel twist erase iii since it has a grip, large eraser and comes in 0.9 mm. It is also super affordable and frankly, nearly all pentel pencils have solid mechanisms. Weakest point of the pencil is the clip, but it is fine with normal use. http://www.amazon.com/Pentel-Twist-Erase-Automatic-Assorted-QE519BP2-K6/dp/B0047CP6SI

I will say though that if you are having trouble with lead breakage you should try one of pentel's or pilot's higher quality leads - something like this - http://www.amazon.com/Pentel-Stein-Mechanical-Pencil-C279-2B/dp/B004NNM5LC?th=1&psc=1

I linked a slightly harder lead than the standard HB lead (a.k.a. #2) which will also give you some strength.

I disagree http://www.amazon.com/Pentel-Twist-Erase-Automatic-Assorted-QE519BP2-K6/dp/B0047CP6SI/ref=sr_1_4?s=office-products&ie=UTF8&qid=1302914995&sr=1-4

These are my favorite, although I use 0.7mm lead. I've been using them since 2001, I managed to break one once, but it's not likely to happen unless you're trying. The only reason I've ever bought more than the first pair was my own carelessness, I lose pencils like nobody's business.

Have a look at the Twist Erase III in 0.9mm (it also comes in 0.5 and 0.7). The grip is quite comfortable and it has the best mechanical pencil eraser ever.

My favorite mech pencil of all time.

Doesn't have cushioned lead, but the .9 will never break. Rotate the pencil to maintain a sharp point.