Since Turner isn't currently making a Rune competitor, I guess I can add more detail
I think the "cons" Rene mentioned are unique to the spitfire. Not sure, I haven't ridden a spitty, but the rune does very well with slow/steep/tight/droppy type stuff. In those conditions it feels more comparable to the 7" highline I owned previously (but with a shorter wheelbase)- both in suspension and stiffness. Until the terrain levels out, then the weight and pedaling performance feel more in line with a 5" bike. The trade-off for all this is, again you will notice some chain stretch especially when climbing with a coil shock.
The rune and spitty are close in weight, so why not get the rune? I think the difference is in geometry and suspension feel. The spitty probably pedals better, and has lower center of gravity to go with less travel. The rune is plush but taller and has more chain stretch. The rune feels more "light free-ride" than "all mountain" to me, but that's probably my build kit...
It's funny that the Runes BB is only about maybe 3/8" lower than my '08 RFX, but the Rune feels way lower. Not sure why.
Lastly I found the Rune feels incredible with the Elka coil shock, but that also brought out more chain stretch, only in the granny gear. Going 1x9 with a 32t, 12-36 cassette has pretty much negated the chain stretch issue, but oh so plush. I couldn't have turned those gears with the TNT suspension, but the banshee squitrs forward with every pedal stroke (I am sure the DW turners do too)...so single ring up front has been great.]