Dynaco ST-70 Series 3

Does anyone know what’s going on with this amplifier? Seemed about to be available some 3 years ago by Canadian firm Radial Engr. Currently no where to be found. Also, any opinions on this vs. an updated oldie but goodie? 
Don’t have any experience in the tube game other than the understanding that I’m missing out. Are they a pain in care and feeding? Breakdown often?

Thanks in advance.