Looking for DOCTRINE FITS?
They say it's worth saving the best until last, and while I wouldn't go so far as to call any ship in Eve the best, the Vexor is certainly one of the most interesting ships in its class. In terms of potential offensive power, it's hands down the most powerful T1 cruiser available - nothing else even comes close. The word 'potential' is important here, and we'll come back to that in a moment.
The Vexor Navy-Issued cruiser was originally designed to carry advanced on-board technologies requiring a great deal of skill to operate, but at the last moment the Federation Navy decided to scrap the more complex designs in favor of simple upgrades to the standard Vexor's armor, shields, hull and drone bandwidth. The result: a monster of a combat cruiser.
Gallente Cruiser bonuses (per skill level):
When it comes to fitting, the Vexor is very similar to the Rupture - its 4/4/5 slot layout is identical aside from losing the Rupture's utility high, and it's even about the same speed (the Rupture is marginally faster, but the Vexor's lower mass tips the balance in its favor when both ships are running their MWD). While most Vexor fits tend to lean towards armor rather than the Rupture's preference for shield, most of the common fitting choices are the same for both ships. The main difference between the two is in their choice of weapons, and that's where the Vexor gets interesting.
The Vexor is, first and foremost, a drone boat. It boasts a very reasonable 75mbit/s of drone bandwidth - enough for a maximum damage combination of two heavy drones, two mediums, and one light - along with 125m3 of bay meaning a little room for spares. This is complemented by a 10% per level bonus to drone damage and HP, making each flight of drones even more deadly. With its max-damage drone wing alone, the Vexor already has a higher maximum damage output than most other cruisers (between 300 and 450dps depending on the number of damage mods). Of course, the Vexor isn't just a drone boat; it also gets four turrets along with a bonus to hybrid damage - only slightly less turret damage than the Moa! That means that at the lower end - with an armor tank and minimal damage mods - the Vexor can put out something like 600dps. For perspective, that's about what the Moa is capable of all in. Switch the Vexor to a shield tank, allowing more damage mods and bigger guns, and that number goes up to nearly 900dps! There are battleships which don't put out that much damage.
Now before you get too excited, I mentioned that this was the Vexor's potential damage output. That's because while 900dps is by no means an imaginary theory-crafting number - a shield Vexor can in practice put out that kind of punishment - this is only going to happen under optimal conditions. That means when a target is in blaster range, and is the right kind of target for the Vexor to effectively utilize its heavy drones. When the Vexor is using light drones (for example to engage a frigate), those drones are only going to add about 200dps instead of the 450 or so that it might get from its max-damage flight. Similarly when fighting something like a Rupture that's able to control range, the Vexor might not be able to apply its full turret damage and that's going to cut its actual damage output nearly in half.
The Vexor is actually quite a flexible ship - it's fairly fast (particularly the shield version), has plenty of fitting options, and can project at least part of its damage out to whatever range it chooses. However, its main strength is as a brawler; let a Vexor get on top of you, and it's one of the toughest (if not the toughest) cruisers to beat. Like most drone boats, it's not unusual for the Vexor to give up its high slots for a rack of energy neuts. This can play havoc with any active tanker, as well as making the Vexor a great asset for combating hostile logistics ships when operating in gang.
If you're taking on a Vexor in a frigate or destroyer, you're probably going to have a bad time. Despite the fact that light drones mean lower maximum dps, they also happen to be very good at hitting those tight orbiting frigates that medium turrets can't. Thankfully even light drones have problems staying close to fast moving targets, so if you're able to orbit wide and quickly (think 4km/s or more) you should be able to reduce drone damage substantially. If you're flying a brawler, you're going to need to rely on tank - and luck - to stay alive until the drones have been cleared. Remember that the Vexor's drones are up to 50% tougher than normal, and that it will usually be carrying multiple flights of them. The standard choice is to carry one max-damage flight, and either two light or one light and one ECM. However some pilots will use a full flight of mediums as their main dps option, with both a second medium flight and one light, or multiple wings of light drones, in reserve.
It's important to keep in mind that drones only account for part of the Vexor's damage output, and killing them won't do you much good unless you can evade its turret damage too. Regardless of what you're flying, your first priority should be getting outside or under those blasters, then you can deal with the drones. The former is fairly easy, the latter is very hard - particularly if you're facing an armor Vexor which is almost guaranteed to have one web, and quite likely to have two. If you're flying a cruiser or larger, clearing drones is generally not a priority; if you can evade the Vexor's turrets, it's usually better to simply go for the ship and burn it down as quickly as possible. This is especially true if you're facing the shield variant - these are notoriously fragile, with some variants going as low as a single slot shield tank in order to mount a web. The armor version is tougher - similar to an armor Rupture or a Moa - but as long as you can keep outside web range it shouldn't be insurmountable.