It was not 'stuff'. Those were very serious systems. And the technology used - transistor or not - has nothing to do with the definition of a computer. I worked on some of the first transistorized systems and they were not all faster than the ones with tubes.
The real bereakthru came with RAM - or core storage, because some of the earlier ones had drums in lieu of RAM. If you want to check it, compare e.g. the IBM /650 with the IBM 1401 - the first ones had a whooping 1200 bytes of "RAM".
Right, the ter Computer is really loose in this time. It is not black and white as a lot of other things. The further you go back the more preimitive the technology gets and the less and less things look like computers. Just because it doesn't use electiricity or Hard Disks or Solid State Drives or...doesn't make it any less of a computer. The world had to have those inventions before it could have what we have now. All things came from them, and all things that are to come will come from now. In the future people will be having this discussion about i7 processors..."they are not computers, cause they had multicore 45nm chips on dies. Not to mention that it didn't work on the graphics and sound processing. blah blah blah".