Others here can give much better advice than I can when it comes to pa speakers as a monitoring option but if you like the QSC K series I think the K8 would be worth looking into if you could audition them at a local store. They are less money, lighter in weight by 5lbs and a smaller footprint if you are playing in tighter quarters but have the widest dispersion pattern of the k series. I have a friend who's band no longer use a back line and have went direct with their bass and guitar, they and are running their signals through stage monitors with good results. Again, others who use stage monitors can give better advice than me, but I would think it advantageous to place the monitor in front of you.
As for me, the Eminence EM12 is working out very well since I found a different approach in how I set the monitor out eq. I haven't had the opportunity to play my guitar for over three weeks, so before I replied to your post I sat down and played for about fifteen minutes. Having been away from the Kemper for a while my initial reaction this morning was this, my rig sounds great! But not my playing !!
Have been putting the qsc behind me, but putting in front front(like a traditional monitor) is something I'll have to try. Thanks for the suggestion!
I hear you on the "my rig sounds great but not my playing". Way too familiar with that scenario