Asics just debuted their GT-2150 model and I am happy to report it is very similar to the GT-2140 https://drshoe.wordpress.com/2009/01/13/asics-2140-has-arrived/
I am a huge fan of this series as it is one of the few shoes that works for the narrow foot. Although the GT-2150 model is ever so slightly wider than the GT-2140, I don’t think this will be a problem for most feet.
All in all, the 2100 series remains one of my favorite running shoes and I will continue to recommend it for many of my runners feet.
Dr. Jenny Sanders Shoe Blog 
I just purchased my second pair of 2140s. I’ve been very happy with this series as well, being that I have a narrow foot.
I’ll switch to the 2150s when I stop finding 2140s on sale. 🙂
Karen
I just switched from new balance to the 2150. Hoping that they are as good as everyone says.
I have been running in the GT2140 for 2 years now and I just bought a of the GT2150. They feel great but I have noticed my left knee is hurting after 10+ miles. The fit is a little different, it is a little tighter and the arch is a little higher
My findings actually show a slightly wider last than Asics 2140 which would allow more side to side motion of the foot, in turn affecting the knees. Because the difference are minimal however, I would continue running in the 2150’s only keep the mileage lower for the first few weeks and see if the knee pain doesn’t just go away.
-Dr. Shoe
have worn 2120, 2130, 2140 for 3 years of running. now 2 weeks into my 2150’s I have pulled both calf muscles running my usual easy 5km. not impressed so far, 2150’s seem rigid and tight