[Therion] PDA

Hi all, slowly the time goes to end, there we can buy cheap "old" PDA with Winmobile. Pockettopo works only on Win platform and small cheap devices with Windows as OS are seldom. And our devices in use are growing older. What do you all use? What alternatives are possible. I know about some so called APPS for Android, but do they work? I hope you have the same opinion - that this is the right platform. Greetings Markus