It is very different. The warfighting aspect is kind of a very, very stripped down version of HOI's (IE: division-based, though you only have infantry, irregulars, cavalry and dragoons + various brigades) Unlike HOI2 (which is all about the war) and EU2 (which is all about diplomacy/expansion) Vicky focuses on the domestic stuff: Building an industry (Revolutions brings a *huge* improvement in this: Instead of building factories manually your level of control is based on the economic policy of your ruling party: So in a laissez-faire economy your capitalists will build factories off their own accord while under a planned economy you have to pay for them yourself) and internal politics. Colonization and war is kind of secondary to this, most of your energy is simply spent trying to balance the budget and keeping your people happy... And now and then invading some poor uncivilized country or waging a Great War against a rival Great Power....
I like it a lot, as you can build all sorts of interesting socities and do all sorts of cool stuff.
True.
Vicky is a lot less wargamey, EU2 has more war in it, but it is rather different. (EU2 is very much a simpler game, but it is, IMHO, the most fun of them, especially in MP (Nothing feels as sweet as haviing your enemy declare war on you in 1620 and then kicking his arse with GIIA) There's still tactics, strategy and force-composition involved, but it's not as detailed as HOI2.