Atmel gives gou many ways to recover from improper boot vector, Philips gives none
That's easy, I do not even care what it is.
Atmel has the boot code in flash, Philps in ROM, I would rather lose a vector than the boot code.

Re block size:
I do not see a program that would benefit from selectively reprogramming a few 128 byte sectors. That does not mean that it does not exist.

The EEprom is nice if you need it.

Anyhow, if you have a need for the things unique to Atmel, use it, If you have a need for the things unique to Philips, use it.

Have fun,

Erik