Posted 28 September 2013 - 03:21 PM
I use an LB 10-X for a number of reasons.
1) The Longbow autocannon are (and there will be other sizes of LB-X) all lighter, smaller (in crit slots), cooler, and possessed of slightly more range than their standard bretheren.
2) There are situations in which you can't get pinpoint aim, such as in a brawl with fast-moving 'mechs (including lights) or when you're moving fast yourself and can't afford to stop. In these situations, an LB-X blast will often hit things that a single shell would completely miss, and 3-4 damage is vastly superior to no damage. (I expect this to mostly not apply for the LB 5-X and not at all for the 2-X, both of which are going to -have- to have slug ammo alternatives to be worth using. The LB 20-X, however, is bound to be oodles of useful.)
3) Shotgun graphics are kinda cool.
4) At very close ranges, the shot pretty much all still hit the same location anyways, unless you're looking at a light 'mech.
5) I like pressing my fire button and hearing that distinctive 'SPAP' sound. Somehow it's more audibly satisfying than the loud 'THUP' of standard autocannon, and it's a hell of a lot easier on the ears too.
In standard Battletech, the tabletop game, Longbow and Ultra autocannon are straight up different-path upgrades of standard autocannon, partly because in tabletop only the AC/10 and AC/20 are really worthwhile, and the AC/20 has prohibitively little ammo (5/ton?). In this game, they went to a lot of trouble to make the standard ballistic cannon viable so that the Longbow and Ultra upgrades are instead Longbow and Ultra alternatives, and given what I've seen while I'm playing, they've pretty much succeeded.
Generally, when I see someone using a Longbow, it's because they feel it's a better weapon for the way they're playing. Since the shift of Ultra AC/5s to the same base reload rate as a standard AC/5, I see Ultras in mostly the same conditions (when they fit what the player is doing better- in their case, burst fire). So, it's entirely possible that for you, the Longbow is a terrible weapon. Nothing wrong with that- don't use it if you can't get the hang of it or it doesn't fit with the way you play.