So I've had my play around, in order to reduce the variables I used a Vanguard warden with 424 racks for a total of 4 size 3 missiles. I played 9 rounds of pirate swarm with each of the 3 missile types and charted hit/miss/kill ratios as well as approximate lock time and range. I didn't fire upon enemies before or during the missile fire animation, so all results are missiles only.
Nova Pyrotecnica Viper 3:
Hits: 14
Kills: 2 (note kills are also hits and included are above, 1x M50, 1 x Sabre)
Miss: 3
Total shots: 17
Lock type: IR (thermal)
Lock time: ~3-4 seconds
Lock range: Highly variable based on the ship and their current heat output, Auroras needed to be within 250m to get a lock, while Cutlasses and Sabres could be locked at 2km plus!
Strike Missile
Opinion:
The cheapest of the size 3s and it shows, missed the most out of all the missiles (probably due to being a strike missile), killed the least and, depending on the target, needs you to be right up in peoples faces to get a lock. It has the shortest lock time, but given how you use it feels longer than the others as it will break more often. It seemed to do better against bigger ships. That being said I got the best action shot, and it does look cool with it's blue shell. Probably the most fitting to people who will be up in the enemies face dogfighting, will probably try it on my gladius.
Firestorm Kinetics Thunderbolt 3
Hits:14
Kills: 4 (1 gladius, 3 M50s)
Miss: 1 (hit a rock on the direct route to the target, barely worth counting as a miss)
Total shots: 15
Lock type: EM (detects target ships power)
Lock time: ~5-6 seconds
Lock range: Very consistent, this missile seemed to always be able to get a lock at 6.8K or less
Proximity Missile
Opinion:
At over 3 times the price of the Nova Pyrotecnica option, you really do get what you pay for here, The Thunderbolt will rip it's way through light fighters which makes it a great option for slower ships, it has a slow lock time so you wont be able to get many locks up close, but at 6.8km range you can easily get a lock in before you get close to engagement range. The thunderbolt feels like the sniper/boom and zoom option and I love it on my Vanguard
Firestorm Kinetics Arrester 3
Hits: 13
Kills: 6 ( 2 Auroras, 1 gladius, 3 M50s)
Miss: 1
Total shots: 14
Lock type: CS (locks onto the ship's cross section, i.e. should be good against bigger ships)
Lock time: ~6 seconds
Lock range: A little less consistent than the thunderbolt, but could still lock many ships at 6.8k, smaller ships like the m50 needed you to be at 2.5k or less
Proximity Missile
Opinion:
CS missiles should struggle to hit small ships, but all I saw was that it needed to be closer to get the lock, however with it's massive lock time trying to get the lock on a good m50 pilot at under 2km would be a struggle. Once you do though wave that ship goodbye. The Arrester didn't seem to hurt the larger ships as much though, cutlasses needed 2 missiles fired at them to get the to be heavily damaged, while for the Thunderbolt 1 was usually enough to send them spinning. However the numbers don't lie and the Arrester has the best kill ratio of all the missiles.
Conclusion:
I'm going to be using the Firestorm Kinetics Thunderbolt 3 on my Vanguard in the future, the consistent long range is great for when you need to zoom out and let your shields recharge and I think it compliments the Vanguard's role perfectly, A rec costs don't really matter the higher price of entry isn't an issue yet and I think it's worth splashing out. Its worth noting that all size 3 missiles pack a punch, anyone in a ship smaller than a cutlass is sent into an uncontrollable spin after meeting any of these 3 fellows, giving you vital time to shoot them down while they are regaining control. The added lethality against smaller ships makes the switch from size 2 to 3 well worth it.