I have 2 155s. I rarely use them. I think that they reload very similarly to 140s for my average sized hand. Like Gooldy, I almost always start with a 170. This past weekend, a stage called for an unloaded table start with a 5 yard run to the table and then a short run top the first position. Based on the round count of the stage, I used the 155, thinking that it would be a little easier to load on the move. I think it is a bit of a niche tool. Maybe if you are starting to buy mags from scratch, get all 155s instead of 140s.