Mechro with shock and siren with fire just depends on your skills. A mech with high anarchy can be devastating if you can hit anything. Also the mech has DT so that's a plus. The siren is more of a team player In my opinion.
When you build a cataclysm maya. She's based around elements. Ruin+ converge. Can grab a ton of enemies. Slag shock corrode and burn them all due to Helios and cloud kill. And then you can just spray and pray and watch devastation. Gauge is one of my next characters to level to check her out. But maya does ridiculous amounts of damage in almost every situation.
I got 3 bad touches before I got my first good touch. I haven't gotten a single bad touch since and I spent 2 hours trying for one tonight.
When it comes to elemental damage, and DOTS, the Siren is WAY better! I have both at lvl 50. Gaige's main element is shock, while Maya can do corrosive, slag, fire, and shock. I'd prefer Maya over Gaige for elements.
I have Dysarthria. It's a Speech problem. Your question is answered now.