[Santa]

Here are some of the differences:

http://wiki.simplemachines.org/smf/Differences_between_SMF_2.0_and_SMF_1.1

Upgrading should also make the forum run smoother.  I would have to modify a bunch of things to make it compatible, but it would be worth it if you guys want it.

[qolderman]

Yes. New is better than old 

[antisickness]

themes look pretty outdated still but if it runs faster I guess so

[Experiences]

Sounds interesting, why not.

[Glacier]

Upgrade sounds great!

[TinyPatch]

Yeah just do the upgrade Kenny.

[leonidsa]

Sounds interesting, why not.

[Cooky]

inb4 we have to pay for features

[Cooky]

im nervous that if it gets changed I wont be able to use forum on my phone anymore    cuz it crashes a lot on my phone

[paranoia]

Can we delete our accounts?

[Selene]

Can we delete our accounts?

Obviously not.

[Allie]

im nervous that if it gets changed I wont be able to use forum on my phone anymore    cuz it crashes a lot on my phone

The primary reason for change is the update will make the forum much more mobile-friendly.