Ok, be prepared, this threads gonna get weird on you (Theres some heated disagrements brewing over the evo thing, forewarned is forearmed as they say)
1) Entirely depends on whether or not you have any opponants in you're local area.
The starter sets an amazingly good deal, but if you have no interest in playing series MI or bugs than its a bit pointless. With some creative deployment and a brain bug and tanker you can field two reasonably sized armies from it. If thats not required it might be easier trying to get the standalone rulebook (Which has lists for Arachnids and series style troopers) and the force you're bugging for
If you want movie style troopers you're going to need to buy the Klendathu source book.
if you want book style you're going to need the MI army book.
If you REALLY like the series you can buy a roughneck army book and box set and use the characters from the series as an army!
Arachnids and skinnies are easier, you just need their book.
2) Evo is the new restart for the game due out... sometime this year... maybe... Basically its being relaunched as a non collectable prepainted game, with 4 properly fleshed out factions:Skinnies, MI, Arachnids, Forth (Who are kinda giant fighting robots...). The rules are also being used for a near future skirmish game called Battlefield evolution, and you can download the taster rules from its section of this website to get a better feel.
The existing models will still be still be usable in this new system, due to the scale being retained.
Will it still be the same game? Well, there have been alot of changes, large and small, and heres where the contraversy comes in.... Basically though without colouring it with my prejudice its an extremly streamlined version of the rules, changing the scope slightly.
For example in the previous version of the rules the axiom was: Units act, Individuals react (So any unit completing an action within 10 inches of a model prompted a reaction), this lead to an extremly cinematic feel for the game with the advantage swinging back and forth during the battle, this resulted in hordes of bugs dying at range, but allowed them to wreck total havok once they closed in.
The new version though runs under a system of: Units act, Units react once per turn. This removes the need for most of the ammo rules, and produce a somewhat more conventional wargame feel, with the games being over a little quicker.
No idea which one personally you'll prefer, but I will say that nows a good time to get into the original version, because alot of stores and ex players are flogging their stuff on Ebay at very competitive prices! Also it'll let you take alook at both versions of the rules prior to the relaunch.
... SotP!
