For tires Mitas is newer player in the adventure market with some interesting options. Mitas E09’s are probably an improvement on the TKC80’s and the E07’s are an improvement over the Heidenaus. There are also Mitas MC60 big blocks which I know even less about, but are probably direct competition for TKC80’s.
On the Heidenaus I’m with Rotarywing. They wear great but are not my favorite tires for multiple reasons, and the stiff sidewall is definitely one. I might run a rear on a cross-country trip but I’m admittedly against the front K60’s (bent rims due to stiff side walls/lower pressure burps, no side grip, rough on the roads, etc). They cost more up front and never give as good of a road or dirt feel as the TKC80’s. I’d rather buy two pairs of the TKC’s.
It will be interesting to get some more feedback on the new Anakee Wilds. Those are still not available in the oil head sizes.