- reduced power usage (34W to 29W)
- new SSE instructions
- better chipset (relating to integrated graphics)
- RAM support for DDR3-800, which is techically more power-efficient than DDR2-800
- Intel Turbo Memory
- LAN controller
- Wireless modules (WIMAX)
Integrated graphics and LAN controller are useless to me. WIMAX is nonexistent where I live and will take time to develop (802.11g is still standard where I live, and connections aren't even stable, forcing me to use HSPDA instead). SSE is too remote to me. As for DDR3-800 RAM, local reviews have pit DDR2 against DDR3. The verdict is that DDR3 cannot beat DDR2 decisively yet since DDR2 is mature technology.
That leaves the reduced power usage and Turbo RAM. Anyway, taking everything into consideration, Montevina is a poor prize to me for having to wait for several more months, not to mention that a new redesign of MBP is needed by then to accommodate the new platform... and then the Rev A issues.
I'm happy just waiting for a week or two for Penryn's proven lower power consumption which translates into better battery life and less heat. That's more important for me.