Sentinel
The Sentinel class is a light suit that focuses on sniping. The BXT1 Rifle is the primary weapon and requires charging up to deal full damage. At full charge it will only do 500 damage, has a slow firing rate and at base level a 4 round clip. Combined with weapon falloff, sniping is much harder in this game than others. The secondary weapon available is the Nova Blaster. This revolver fires a fast moving laser beam that ricochets once off a surface, effectively dealing with most enemies that get close. The Claymore is a brilliant grenade item, acting much the same as most other games. The utility item for this class is the extremely useful Drop Jammer. When deployed this will make everyone in the radius fade and eventually turn invisible. It will also reveal any Infiltrators trying to sneak their way past your defences. This class is one of the harder to play and doesn't contribute as obviously to most game types unless practised.
Infiltrator
As alluded to above the Infiltrator is the sneaky class of the game. This class is brilliant at sneaking into the base of the enemy to destroy and disrupt defences. The opening weapons are the Rhino SMG and SN7 Silenced Pistol. These are both basic ballistic weapons and are fairly lethal from stealth. One of the major weapons the Infiltrator fields is the sticky grenade. Sticking them to your enemies and watching them run is a joy. The utility item is obviously the ability to stealth, which will drain energy but fade you out of sight shortly after taking damage or firing. Going over 173km/h will also remove this effect. This is a fairly basic class to play and, with enough guile, very effective.
Technician
The second medium suit is the Technician. This defensive class is at its most effective in Capture the Flag for a number of reasons. The first weapon is a basic SMG, the TCN4. The secondary "weapon" is an enhanced repair gun with increased repair rate. This limits the offensive capabilities of the technician a fair bit but makes them ideal for base defence. The belt item they carry is a basic fragmentation grenade, with decent damage and range. The utility item of the technician is one of the strong points of the class in its vanilla state. The turret is an automated defensive placement that can be used to defend choke-points and flag points. Although only able to take a couple of hits from a spinfusor this item is superb when used in conjunction with other defensive measures. Due to the static defensive nature and important repairs needed in CTF this class will excel in that game type more than any other.
Raider
The last medium suit is the aptly named Raider. This quick moving attack class is designed to ravage the various defences of the enemies base. The primary weapon, the Arx Buster, has a 3 round clip of sticky explosives. These can be stuck to both enemies and defensive emplacements, although it takes practice to be accurate while moving at high speed. The secondary weapon is another SMG, which proves useful for longer-range fire-fights as the buster has an arced firing line. The grenade weapon for this class is the useful EMP Grenade which can kill a light suit on a direct hit and will also drain energy, useful for slowing/immobilising enemies. The utility item for this class is the Shield Pack which, when activated, will slowly drain energy and remove any damage taken from the energy pool instead of health. This is especially helpful when trying to create a breach into generator rooms or on flag points. This class is a bit more difficult to master than the soldier or pathfinder but devastatingly effective when refined.
Doombringer
The Doombringer is the second heavy suit and has a fairly misleading name. This largely defensive class is effectively a flak cannon, designed to down quick moving and/or flying enemies. The main weapon is the Chaingun, a gatling gun with 280 rounds in the vanilla version. Although requiring a short spin-up this weapon needs no reloading, has decent range and will destroy an approaching pathfinder easily. The secondary weapon, the Saber missile launcher, fires a homing missile and is great for destroying enemy vehicles and any flying enemies. This weapon requires a 3 second line-of-sight lock on which will only activate if the enemy is in the air or in a vehicle. The missile can be shot down or avoided but does 1000 damage on suits and 1400 to vehicles, destroying grav bikes in a single blast. The grenade item is a basic frag, useful for doing any aoe damage with no ability to lock on. One of the major features of the class is the utility item, the force field. This placement will block enemy fire and, more importantly, damage enemies that go through. The faster the enemy is going the more damage they take, leading to pathfinders splattering like bugs on a windshield if the force field is placed near the flag. This class is fairly noob friendly and extremely effective in CTF but can be trumped by other class combinations relatively easily.
Brute
The final heavy suit, the Brute, is a fairly basic class to play with lots of health and very powerful weapons. The primary weapon is the Heavy Spinfusor, a beefed up variant which fires the same but packs a much stronger punch. The secondary weapon is an automatic shotgun, giving the Brute much needed close combat capabilities as the spinfusor is impractical in close quarters. The grenade item of the Brute, the Fractal Grenade or "disco ball", epitomises the Brute. Throwing one of these will clear the area fairly quickly as the grenade fires out multiple random lasers and slaughters any light suits nearby. This is a fantastic weapon for clearing areas and is a great revenge weapon, thrown just prior to death in a small room. The utility item of this class is a basic Energy Pack, allowing the Brute a bit more mobility, in line with its offensive disposition.
The general consensus with unlocking/upgrading classes for free is to choose one of the three basic classes, upgrade the starting gear and practice with that one till competence. At this point you should be able to rake in enough xp in a couple of games to unlock other classes. The more defensive classes, the Technician and Doombringer, may be less suited for modes of play other than the classic CTF as their utilities are somewhat neutered with minimal chokepoints and tunneling. The Sentinel is also difficult to get used to if you are accustomed to sniping in other games. My personal preference is the pathfinder as Tribes has always been about going mind numbingly fast for myself.
