I have five 21s and a 25. I have no issues with blade play or wobble on any of the knives, and they all get used, sometimes hard, both outdoors and at my job as an electrician. The bushing system would be my preference as I feel it is a stronger design (with the bushing firmly sandwhiched between the slabs), and I like the low profile scews, but the 25 is awesome too, and I am unlikely to break either. I also feel I'm getting more for my money with a 21 in terms of the work that went into the knife, but you can argue either side successfully, as I am sure people will. The choice between the two is really splitting hairs in terms of quality and strength, so I think it comes down to which one you think looks better, which grind you prefer, and the weight of the knife. The 25 is heavier in pocket, but looks more impressive. I love both, but a large 21 would be my "desert island knife" in the current CRK line-up......or maybe a 25, I dunno....buy both?