Ok... first off, great shots! The IQ of the lens is amazing!
A little of-topic, I started a thread on which DA* lens combo I should go for... a little while ago, while taking shots of my daughter indoors, I had a very difficult time focusing (I was using a Sigma 105/2.8, notoriously slow focusing...) Anyway, I realized that the 50-135 range is perfect for what I shoot. (Pet portraiture, my kid, and concert photography. All need speed and SDM! weathersealing is a bonus.) I thought the 60-250 would suit me more because of the reach, but saw how much a difference 2.8 is from an f/4.(I tried shooting at f/4, it's workable only if I boost my ISO). I also figured that when doing concert photography, I almost always use my Sigma 105/2.8. The reach is just right. I also checked all the exifs of my cat portraits and almost all FL's used were between 50-135! (using an 18-250, I used a few 47's and 160-200's but 90% of my shots were shot between 50-135! sweet!)
Anyway, sorry for hijacking the thread, I just want to say that this thread had me sold! The 50-135 is definitely next on my list! (after I sell my guitar and guitar effects! trade anyone? Haha)