[mark254]

That's not so tiny... 256 Bytes RAM, 4K Flash, that's quite a bit bigger than the smaller ATtiny25 (128B RAM, 2K Flash, 6 I/O, much less hardware on board)

[makapuf]

Attiny4 has 32B RAM, 6 pins and 0.5KB of flash ... see the whole product range here (pdf link) http://ww1.microchip.com/downloads/en/DeviceDoc/30010135E.pd...

[JAlexoid]

Why would you need more?

I prefer with PIC, as they offer real time very predictable execution. All instructions have same execution time.