I basically consider support my definite niche. It's an especially rewarding position if you have a good team to do the aggro stuff for you (and a good defensive player backing you up), but in Solo it can be rough as I tend to find myself defending against flanks alone against two-three enemies or even just one that has an invincibility special charged.
The Dual Squelcher is my main and I would consider it a pretty great support weapon. Range + Splat Bombs forces enemies to stay back or retreat if they try to get into your zone, and Echolocator is a god send for helping your team push against sneaky players or making sure you aren't about to be hit by a huge flank when things seem too quiet. (especially since teams in solo que rarely ever take the time to spot these things themselves) It's definitely no slacker at covering turf either, but I think one of its best attributes is mobility. Not strafing speed, although it has that too, but being able to move around the map and set up faster than other support weapons. It can defend itself much better than some of the slower support weapons that will have to charge up or have long wind ups, so you can move with the battle to support your aggro players or fall back to defend pretty easily. It's also not terrible at playing a cautious front line if you have good aim and use it properly. I would say some of its weaknesses are a somewhat slow time to kill (compared to other things like tentateks or gals.) and an ink efficiency that, while on paper sounds fine, realistically I find myself running out of ink too often while constantly trying to push others back. However, that may just be my own fault and both of these can be countered with good zoning and ink abilities.
Abilities: A mixture of: Tenacity or Special Charge Up, Cold-Blooded (not necessary, but always a nice pick), Bomb Range Up, Ink Resistance Up (another one not completely necessary), and as many Ink Saver Main and Ink Recovery Up subs as I can get. Run Speed Up also works well with this.
wow wall of text