In my experience (feel free to contradict this), Spiders are better recon lights while Firestarters/Jenners are better fighters. I've seen a few rounds where a Spider D with ECM tore up our team as a spotter (especially on Manifold), partly because they blend in so well on that map. It may not have the firepower, but it can be nasty when used right. Honestly, I'd keep at least one Spider around for that reason, it's a good option to use with ECM, and IMO works better than the COM-D or RVN-3L in that regard since it's so frigging hard to hit for a lot of people. Then you can pull out a Firestarter/Jenner when you just want to move fast and hit hard.
I find the spider 5d to be one of the best mechs in the game. Don't underestimate the power of a stupidly hard to kill, super mobile ECM with energy weapons. I find it easy to consistently put up 500 damage matches as you can maneuver into a position to always be firing.
The SDR-5V always been one of the worst mechs of the game so we won't discuss it. Indeed the SDR-5K now suffers the competition with Firestarters, especially with the Ember. It's still the only non-Hero light mech with 4 MGs so if you don't want to spend MCs it makes a good alternative. It's also one of the fastest mechs, able to run at 170kph while Firestarters cap at 150. The SDR-5D keeps its place in my opinion: best recon/spotter mech (JJs + ECM + small hit-box = yeepee!).
I'm Not a Lights Pro, but from my experience with them i can say that what Durandal and don zappo said makes very sense. The 5D and 5K are great! Don't underestimate ECM and Quad MGs. Firestarters are great too! But from my battlefield experience against them only the Ember i really fear. The rest is handable. If you have the Mechbays i would keep at least the 5D just as the others recommend.
But, but, but...12 jumpjets! The Powah! He can nearly fly! The only mech to jump atop every single building on every map. The V is special! hear: hear: http://mwo.smurfy-net.de/mechlab#i=51&l=c3f00d30f6fad01e73b28afaf8f5539e7d8aecab Admittedly the worst of the Spiders though and I never did play a good game in that mech if I equipped all twelve but nevermind that... I have similar experiences with the 5D and K that the others mentioned, hell, I dropped by mistake in the K model a few months back while teaching a newcomer and I rippped off 5 kills with the trial spider.
But while you would think because of its 12 JJs that the mech is built for verticality, all the hardpoints are in the torso with a ridiculously low 20° pitch. In a word, you can't use your weapons when jumping. This is absurd. That being said, I'd love a mech with 12JJ and hardpoints in the arm.
As someone currently cursed to fail upward in the SPD-5V right now...all I can say is that I would kill to move that hardpoint from CT to an arm. Most painful crap variant I've had to put up with, as far as mastering efficiencies go. Even the JR7-K was better...
The Spider-5K has never been a problem for me; in fact, I'd say that I generally perform better in it (damage-wise) than in the 5D. Here's a match I had a while back. No consumables; just conventional weapons. (4xMG, 1x MPL, 3x Ammo, XL280)
I was thinking about downgrading the large to a medium pulse and cramming the biggest engine possible into it.
