Have you taken a look at the Elcan Specter-DR ?? I have decided to replace my TA-01 Acog with one and have had mine order for about 4 months now, It will be in around December. I've seen two for sale over at ARF.com. Though it's a little more expensive than the M145 and OS3.4, It's less bulky and has the ability to switch from 1X to 4X and has a battery operated LED, hence no tritium replenishment issues.