136 is deep in the corners of left field. The left field foul pole is in your peripheral though it won't obstruct you view of the plate like it will from section 137. The only plus would be that in the first 11 or 12 rows, there are very few seats in each row so you can easily get in and out.
If there is a right fielder you particularly enjoy seeing play though, you basically have front row seats to their plays on the field. You can even shout at them and they will probably acknowledge you at some point.

I think Chase Field is one of the few MLB ballparks where fans are comfortable walking around after games. (Try walking around in south Chicago after a White Sox game). It's right in downtown Phoenix and there is a light rail stop outside of it so it's easily accessible.