Disclosure: I am a fan of Openquest. I was one of the backers of the Indiegogo campaign for OQ2 (I am thanked by name on the general thanks page, along with other contributors to the campaign).
Openquest 2 contains zero fundamental changes to the mechanics of Openquest. Instead, it provides more spells, better explanations of gameplay and how to tweak it to suit your style, a brief realm system, some new skills, and colour pictures. Broadly speaking, a lot of the changes are incorporating material / inspired by other systems, including other versions of BRP (Basic Roleplaying, the percentile system that powers Runequest, Stormbringer, Call of Cthulhu and other systems). Sometimes this is good, sometimes it seems extraneous.
The two new skills are Wealth and Relationship (X). Both at optional, so you don't have to use them if you don't want to.
The Relationship skill is basically a passion-system like other BRPs have, and is something I really dislike outside of its use in Clockwork and Chivalry, since it rarely does anything directly in any of these games (typically, such skills add their tens digit as a percentile bonus to another skill). At least in C&C it represents one's ideological commitment to some position in the Civil War and comes up whenever you try to proselytise for your side or resist proselytisation by another side. I'm very leery of skills - and older versions of BRP are notorious for this kind of skill - where having them doesn't allow one to do anything different, it simply gives one a bonus to some other skill roll, or allows one to make a second kind of skill roll under certain conditions one otherwise couldn't. The Relationship skill here collects a bunch of fuzzy benefits together under four headings (Allies, Dependents, Enemies and Organisations) with different benefits in each case. If you wanted to create something like the D&D 3.5 Rangers' specialty enemy ability, this would allow you to do it. One of the things I like about Openquest is that it tends to give you clear expectations - whether in the form of concretely defined actions one can take, or in the Big Bonus rule - and I find that the relationship skill doesn't really do that.
Wealth is the typical BRP skill for people who don't want to track individual coins or assets. I go back and forth on this skill, since it mainly exists in games to represent credit but does a bad job representing how credit works or how it motivates people to act. This isn't OQ2's problem tho', it's really a problem with Call of Cthulhu / the BRP gold book, which use this skill. Personally, I think I would stick with the individual asset approach, at least at lower levels of play. This skill has all sorts of sublevels and requires you to determine where specific pieces of gear fall (tho' it provides a chart with some guidelines) so you know what kind of stuff you actually have to roll for or not.
The spells are strong, and good additions to the system. Openquest is now in competition with Runequest 6 for the best battle magic system in a BRP-type game.They're mostly fixed-magnitude, and appear inspired by various low level spells from D&D (this is good), though there are some progressive ones that upgrade. There are a few "extra action" type spells, which I am mixed about. Multimissile was already in the game, but new ones have been added, and I worry that this will create an action / magic point economy at the higher levels of power and transform high level combat into managing it. Still, overall, the additions to the spell lists (not just battle magic, but divine and sorcery as well) are welcome.
The Realm management system is mostly about quest generation, as it should be, and includes notes on using the quests for the various power levels PCs will be at. Like most stock OQ work, it's pretty sparse. I may expand on it and the attached mass combat system sometime in the upcoming year.
The game in general includes a lot more advice on how to play it, which is good for me, as I use Openquest to introduce people to BRP-type systems. I would feel more comfortable handing OQ2 to a new referee than OQ1, now that I have the option to choose between them. The examples are more fleshed out, different campaign power levels are discussed, and there's some discussion of modifying the base assumptions (i.e. different types of magic available and how) to help you create a particular feel.
So, I like Openquest: It remains one of my preferred systems for fantasy roleplaying games, and I will continue to use it for such in future. Openquest 2 is more an extension and continuation of that source text that a radical revision of it (the two are fully compatible, which is nice as I already own three well-loved copies of Openquest 1). I would recommend picking Openquest 2 up for all the same reasons I recommend picking up Openquest 1. I don't know that it's dire and urgent that you switch over if you're happy with Openquest 1 already, but if you like it and want more spells and options, it's worth checking out.