Ok, so I have not switched (yet), but I also play the 981s. One of the main reasons I have not made the leap to a new set, is that I have not found another iron that feels or plays better than the DCI 981. That was until I demo'ed the AP2 irons earlier this Summer. I am now about 75% of the way to having saved enough to buy a set. I also tried some other brands, and both were comparable, but like you, I'm a Titleist guy. I just wish the Titleist irons weren't so much more expensive than other companies. $200-300 per set is a big difference. I work for a non-profit and do not buy a lot of equipment, and when I do, it is going to be in my bag for years (eg, 981s for 10+ years and counting). Plus, if you are custom fit for Titleist, they still come with a lifetime warranty for loft and lie adjustments, and I believe shaft replacement, but not totally sure.

Like others will tell you, go try them and find what you like. Try them outside so you can see ball flight and feel on the turf.