I still say Gottlieb and here's part of why...
"System1 was Gottlieb's first series of solid state pinballs introducted in late 1977. Gottlieb was the manufacturer leader in EM (Electro Mechanical) pinball. But they had a hard time making the transition to solidstate pinball. They were also the last manufacturer of the big four (Bally, Williams, Stern, Gottlieb) to switch to solidstate technology, and even made some games in both solidstate and EM formats until 1979 (where the other manufacturers had abandoned the EM pinball format since 1977). Bally and Williams had been working on solidstate architecture for since about 1975, and fully adopted the technology by early 1977. Gottlieb on the other hand hired Rockwell to design their solidstate pinball boardsets, and were the last to enter the solidstate market. This was a mistake that Gottlieb endured for over 10 years, as Rockwell did not serve Gottlieb well. " - pinrepair.com
Now, would I buy a Gottlieb machine after having new updated boards, sure, I think many would. And of course any 30+ year old technology would need to be updated to todays for any manf, but the original question was what manf, thus I stand by Gottlieb and my Haunted House and Charlies Angles examples.
So a machine is as reliable as the electronics in it. If it's all original, then it will be less reliable then one with updated boards, strictly speaking for boards that had known issues from day one such as these Gottlieb.