From Experience...

And so Apple reached the end of the 100 line with the PowerBook 190. The only machine in the 100 series that sported a 68040 processor (although it's technically the FPU-less version) the 190 is almost identical to the PowerBook 5300 - not that this is supposed to be a recommendation or yardstick.
My 190 came to me, as per usual, via eBay. Sold as 'untested' I was actually very surprised to find that it booted first time and was actually in excellent condition - even the port cover on the back was still in place. Gone though is the dark grey plastic and instead the 190 is black, which kind of sets it apart from the rest of the series. Being built alongside the 5300, the pair can swap many parts and as my machine sported the greyscale screen I decided to plug in the 5300's colour screen. Amazingly it worked and everything was in glorious colour but the fact that the colour screen is thicker than the greyscale screen meant that the upper case wouldn't physically fit anymore - so it all had to be put back. Shame that.
Performance wise the 190 is no slouch. Ok so it isn't going to win any speed contests but it is faster than any other 100 series machine and it's more than up to the job. The passive matrix display isn't as good as an active matrix one (obviously) but it isn't too bad and is certainly isn't in the same league as some of the other hideous displays that are out there in PowerBook-1xx-land. My machine came with a whopping 25Mb of RAM but it's worth noting that while many components can be swapped with the 5300, memory isn't one of them (I know, I tried it).
Would I recommend one? Yes I think I would. The colour version is brilliant but even the greyscale version does a good job and is more than up to the job of writing the odd letter, playing the occasional game or even browsing the internet. And let's be honest, what else are you going to do with any machine of its age?