I've owned a ARC D-115 Mk 2, Dynaco ST-70 and still have MC-60's all of which are great vintage gear. So far as looks go, definitely the McIntosh amps which I still have. So far as sonics go, the D-115 Mk 2 is a great performer though I found the bass a bit fatter, not as defined, and the highs a bit beamy, and glassy at times than the better crop of current tube amps although it has plenty of slam. This amp has one hell of a soundstage and a great midrange and plenty of power, 100 watts. A real classic, I hated parting with it but you can't keep them all.
Most of the all tube ARC amps from the 70's and 80's including the D-70 M-100's, D79, D-250 are all quite desirable and great vintage stuff.