PlanetSide was clearly the result of a lot of ambitious planning, but much of the game experience depends on technical stability and the performance of other players.
Unfortunately, putting together a good group and actually coordinating a successful assault can take a lot of time. Essentially, you'll stand around doing nothing, or next to nothing, and shouting on the broadcast channel to get invited into a squad. Then you'll wait as the rest of your squad forms, wait for transportation to your destination if you yourself can't pilot a vehicle, wait to actually arrive at your destination, and wait for everyone else to arrive. In the worst possible case, with no vehicles available, you may end up waiting for your teammates, or your own character, to finish walking all the way to your meeting point. You have the option of using a universal transport known as the High Altitude Rapid Transport (HART) to travel directly to your destination, but unless everyone in your squad takes it, your group may end up divided on arrival. Basically, you'll encounter a surprising amount of inactivity--especially for a game that's supposed to be a fast-paced first-person shooter--as you wait for everyone to assemble. You can join an outfit, PlanetSide's version of a persistent player "guild," and while chatting with your fellow outfit members can help get you into a squad faster than randomly shouting for a group, it won't make coordinating an operation any less time-consuming if no one has their act together.
But if you can put together a good squad of skilled players, PlanetSide can offer an exciting and highly distinctive first-person shooter experience. You may have played other multiplayer shooters with team-based objectives such as attacking or defending certain positions, but you've probably never played one in which your character's next permanent experience level (and his next set of certifications) is on the line. PlanetSide makes a few feeble attempts to get you interested in the story of the war between the three playable sides, and you can actually help your faction take over entire continents, but this control really only means you can travel through those territories safely--there aren't any really meaningful incentives to continue to defend a particular territory, and you'll often find that control of various territories changes hands between the three factions regularly. However, you'll find well-organized battles to be exciting enough on their own. Successfully surviving heavy fire, putting down your enemies, and hacking their base can net you an extra battle rank and new certification points, while getting shot down often means a long walk back from your last spawn point. Better still, if you're the leader of a squad, you also stand to earn command points that can be used to increase your rank as a commander within your faction. Increased rank currently earns you perks like the ability to set in-game waypoints and even send broadcast messages to an entire continent, though the command rank feature itself will likely become more important as the game (and its players) mature, and as Sony Online Entertainment expands on it.
It's these potential rewards and losses that really help distinguish PlanetSide's battles from what would otherwise be standard sci-fi first-person shooter firefights. Depending on which certifications you choose, you'll be able to use assault rifles, grenade launchers, miniguns, sniper rifles, and others, and these weapons behave much like they do in any other first-person shooter. In addition, you, your teammates, and your enemies may acquire certifications to wear heavy combat armor or stealth armor and to lay traps for your enemies in the form of mines and grenades.
PlanetSide uses the same sort of lenient physics used in arcade-style first-person shooters, so any skills you may have developed in other games should transfer over to PlanetSide intact, as should any team-based skills you may have developed as a medic, pilot, or driver in other team-based games. The different armor types, weapons, and vehicles collectively add a good deal of variety to PlanetSide's battles, which are, at their best, at least as interesting as those in other popular team-based games such as Battlefield 1942 and Counter-Strike.
Unfortunately, it can sometimes be difficult to truly enjoy PlanetSide's battles because of the game's occasional but exceedingly annoying stability problems. The game currently suffers from periodic bouts of lag that can at best break up the action and at worst get you killed by enemy fire while you remain rooted to the spot. PlanetSide also currently has some problems with crashes and disconnects (or "going linkdead"), which can break up a squad and, in rare cases, thwart a last-minute attempt to recover from a failing attack or defense effort--if you're on the verge of losing a campaign, having some or all of your squad get disconnected can very well mean certain defeat, despite your best efforts.
PlanetSide was clearly the result of a lot of ambitious planning on the part of some very talented designers, but as it stands, much of the game experience depends on technical stability and the performance and skill of other players. In terms of stability, PlanetSide isn't where it needs to be yet--the game still suffers from annoying lag and disconnect problems that need to be fixed. In terms of player skill, you'll find that although the game's strict handling of "grief" play helps encourage players to work as a team, your enjoyment of the game will largely depend on how experienced, skilled, and focused your teammates are. The less organized your team is, the longer you may have to wait for it to assemble, deploy, and formulate a plan of attack at your destination. However, if you think you can surmount the game's learning curve and whip a squad of like-minded recruits into shape, you'll find that PlanetSide offers a unique and potentially very enjoyable challenge.