Ah, the Centurion. Solid, dependable, quick, hard to kill and cheap. A quality robot beloved by all - and yet when it first showed up, the goon hive mind found it wanting. "Ballistics mounted on that massive arm?" we cried, "and missile bay doors that make landing a volley on someone unnecessarily difficult? Piss to that."
What changed, then? Why is the Cent the medium we recommend to newbirds wanting something in the weight class? Well firstly, the bay door control got introduced, so missiles now fire when you click the damn button instead of half a second later. And secondly, someone took the time to reevaluate the cent and found it was awesome. It's one of those mechs that just refuses to lay down and die, forcing opponents to devote more concentrated firepower to kill it than other mechs of the same tonnage. With the way the Cent's components and hit boxes are laid out, a pilot with a degree of skill (and a standard engine, for god's sake don't put an XL in one of these) can spread damage over the big fat arms and wide side torsos, delaying death for ages. All Cents have centre torso-mounted lasers too, so as a rule if you're alive, you're still a threat. Here follows a quick run through of all the Centurion variants with some suggested loadouts for each. The three standard variants are all capable of very different playstyles and all are fun. Also, there's the Yen Lo Wang.
This is the original, and my favourite Centurion variant. Coming stock with two medium lasers, an AC/10 and some LRMs, in canon the Centurion was built as an operating partner for the Trebuchet. It's a bit of a weird pairing, as both mechs come stock with LRMs and lasers - the only real difference is the Cent drops 20 LRM tubes and a laser in favour of the autocannon. To make the most of the -A, you're going to want to strip all of that stock kit out apart from the lasers. Then jam a big fat engine in (260 or 275), endo steel, ferro fibrous, double heat sinks (and some SRMs), and you've got a mech that can do 90kph and has an alpha that can't really be ignored, like so.
The -A is best used as the brawly Cent, and a skilled pilot will keep it alive and unloading missiles for a ridiculously long time. It's lost a little of its teeth since SRMs had their damage reduced and splash damage removed, but it's still very hard to kill. It may be worth holding off on the -A at the moment though, and start instead with its lasery brother.
Suggested modules: Seismic Sensor, Sensor Range
Any brawler can make good use of the Seismic Sensor. It's really handy to be able to turn a corner and know whether or not you're going to get shot at. Sensor range is rarely a bad choice either - you don't necessarily need it, though. I honestly think that Seismic is probably enough for this robot.
The -AL drops a missile slot and the arm ballistics to fit a couple of arm-mounted lasers instead. Now, you can kit this out like the -A build above if you want, trading out one SRM for two medium lasers. That's not a bad build at all really, and although it runs a tad hotter than the -A, it's a bit more effective right now with SRMs being messed up. What's possibly more interesting, though, is to try something entirely different. Stick a 250 engine in there and load up with three large lasers - now you've got a completely different playstyle to the -A, one that involves sitting at 300-400m and drilling people to death with lasers.
Hang with the assaults and heavies, let them tank the shots coming inward, and lock your arms to the torso, and you've got a recipe for dealing a lot of damage to components of your choosing. You're also pretty quick, so you can reposition a bit more speedily than, say, a laser drill Stalker. One of these makes a good complement to a team built around sniping, especially if you're playing around with weight or class restricted group compositions. Even if you're not, it makes a nice change from the way a lot of mediums play. It's a good idea to crank down your mouse sensitivity when playing this robot - it makes it a lot easier to keep your lasers on targets at range.
Suggested Modules: Sensor Range, Target Info Gathering
Sensor range is a bit more handy here than on the -A, as it's useful to be able to see exactly what's coming from as far out as possible so you can set up properly. Target Info Gathering will let you work out more quickly which component you want to drill out.