LRMs are great!
Although some mediums and even lights can run LRMs well, most of the time you'd like to have a heavy or an assult. But, that sounds just an opinion, lets use some facts, of course these are unfortunately very personal facts, but facts all the same.
First, my stats sorted by average damage. In same I explain most common loadouts from the top mechs. Second picture is sorted by Win loss ratio, since at least personally I respect winning more than damage.
The Archer 5W with 9 missile hardpoints has pretty much always run with 9xLRM5, XL 340 and then lots of missiles and maybe few extra heatsinks. That is a really iconic and well working boat. That would be a good baseline for LRM assult, except it's more like a ceiling. Now it's a heavy but that's really one I've been most broud of.
After it's success I wanted to have something with bigger caliber, thus I took Stalker-5M. Not only or purely because it has 5 missile hardpoints, but because it has 15% range quirk for them. I've run it with mostly XL 250 or XL 310. Yeah with Stalker having XL engine sucks a lot more than with Archer.
I wanted to have something that affords more aggression as it has energy hardpoints unlike Archer, so I've pretty much always had a tag and for long time Artemis as well, only recently I desided I can't make artemis work on it and it wastes tonnage and slots. Stalker really lacks tonnage, for an assult. If you take LRM5A, you will waste a lot of slots and tonnage and that's not really effective. LRM10A gets a lot more heavier and it has more spread. I think my most successul buidls have had 3 large pulses along with something like LRM5A, or 3-5 medium pulses. Or could I have LRM10A with them, I can't remember.
I really wanted it to be a nice LRM boat but it's been a let down a bit. If Cyclops would have been on sale when I got the Stalker, I'm fairly sure it would have been better, due to higher tonnage, much more missile hardpoints. But Stalker was on sale and Cyclops wasn't.
You can see the Stalker is pretty high in average damage but specially few games ago, the W/L ratio was the letdown, something between 0.7 and 0.8 I recall. I also lack the ability to carry two modules, as that 1250 meter range really doesn't work when your own sensor range is only 1000.
Now latest addition has been Warhawk. I took B variant since, yep you guessed it, it's the one with missile hardpoint on CT. I think I've been mostly running it with 4xLRM15, tag and 3x medium pulse. It's amazingly fast, it allows good aggression and it takes quite a beating too. If you compare that to my Dire Wolfs, yeah, they are hardly in the same ballpark.
If I want to win, I carry lots of LRMs. YMMV.
Only recently Warhack surprassed Archer in W/L ratio. In next patch LRM5 will get same spread as LRM10 so it will likely hit the Archer somewhat, but hopefully the skill tree will get get implemented at the same, as it offers pretty nice spread and heat skills to take.