All variants share a lot of common features: It's a 30 ton light on par with the Spider, Urbie, and Javelin. All come with FF, EE, & DHS preinstalled. All run XL 245 engines stock with a 285 engine cap. Stock speed is ~130 kph. All of them also come with 4-8 Jump Jets.
For my personal play style I opt for the speed tweak skills on all new lights and mediums I play and for the Osiris I pretty well universally upped the engine to an XL 255 (or more). I considered Light engines for it, but decided against it as it cut into the mix of firepower, armor, and speed to much for my taste.
Overall impression: Can take a bit of a beating even without skilling for durability. Also can hit hard for their weight.They also can reach speeds up there with Locusts and Commandos. This makes them great strike and fade mechs. Dashing in and out of fights as needed. It's one big downside is IS missile launchers are heavy and most deigns of the Osiris don't get more than two launchers. It feels like two is just not enough in most cases and suffers . It also lacks ECM, so you need to be more careful.
Now for the variants:
The 1P is my least favorite. A pair of launchers doesn't feel very strong here. Also if you want to go with ballistics (ie quad MGs) that's at least 3 tons minimum. To top things off the energy is a set of two in the CT. Limiting you to either a pair of lighter lasers or one heavier laser. This makes it a lot like a Locust 1V and 1M combined into a single mech.
The 1V is one of the few non-ballistics variants. Instead giving you a third missile launcher along with 4 energy weapons. This does mean you can do a 3xSRM6 build, however this is basically all your tonnage requiring 9 tons without artemis (12 tons with). With a XL 240 engine, stock FF/ EE, and max armor you have 10.64 tons available. Even 3xSRM4 is hard to fit leaving you ~4 tons after fitting the launchers only. Honestly it's easier to build this as a energy weapon platform.
All other variants are functionally identical mixing some MGs with energy weapons... Only the 1P lacks at least 4 energy hardpoints and the 4D has 6. Most often these hardpoints will carry Medium lasers (or smalls). The 4D can deadside with no hardpoints in the left side. The 3D can sort of do this as well if you forgo the missile launcher, this leaves just 2 ballistics in that side. So most play very much alike.
Comparisons:
Locust: The Osiris and the Locust can hit the same speeds and tend to have similar loadouts. So the Osiris can be said to be a larger, slightly more (physically) durable Locust. The biggest difference is no ECM or Stealth armor option for the Osiris. The Osiris does also carry jump jets, which can be very useful.
Firestarter: The FS9 is another platform that is primarily an energy boat for small and medium lasers, however it's not as fast as the Osiris. It does however mount a few more lasers.The Ember and FS9-H also carry ballistics making them very much like the Osiris in builds. They also both have jump jets.
Wolfhound: The wolfhound is the other IS light energy boat the Osiris needs to be compared to. Just like with the FS9 the Wolfhound is slower than the Osiris, and in this case lacks jump jets for that added mobility. However it is more sturdy and has similar weapons loads than the Osiris. Having gone 1 on 1 with a few Wolfhounds it's often a draw as to who can win such a fight.
Arctic Cheetah: The king of lights also tends to be a energy boat with ballistics options. However as is usual between IS and clans, the clan option tends to be better. The Osiris is faster, but in my experience I seldom win one on one and running away can be very hard from a ACH in the Osiris.
Edited by Shadey99, 26 October 2017 - 07:13 AM.