There are no "better" versions of your weapon than the stock option. They all come in fixed, gimballed, or turreted variants. Lately I've been having trouble finding burst lasers, though.
I think I'm going to shoot for the Cobra Mk. III for my first upgrade ship. Affordable, looks like a solid all-around choice. Good jump range, decent speed, decent cargo hold and a fair number of hardpoints. I like its multipurpose role.
Anything bad about it? Good choice?
You better plan for 2 million creds worth of upgrades then, unless you plan on doing nothing but mining & trade runs with it.
The Adder is more cost effective, more maneuverable, and makes a better smuggler when running illegal missions. The Cobra's high top speed, especially on boost, can cut down on a lot of time and makes it the ultimate pursuit ship. If you want to go straight for the Cobra that's fine, but I would recommend shooting for an Adder and planning out rare item trade runs. They're not
as lucrative as they were in the Gamma, but some stations can put out a fairly large quantity of rare goods.
Right now, while the Onionhead event has been running for Kappa Fornacis, Harvestport has been retaining inventories as high as
17 units of Onionhead. It's illegal in most jurisdictions so you would need to stick with Anarchic systems, stations, or outposts. Outposts never scan you for illegal goods in my experience, because they never have a System Defense patrol. Carrying 16 tons of Onionhead in an Adder out to a destination roughly 160 lyrs from Kappa Fornacis can net you a score of 250,000 credits profit for an hour's run. It takes a while for the market to fill up, and you can buy a few then buy more as they refill, but 17 units is the max player limit I've seen for Onionhead. Yes, this is what I've been doing to make money since I blew up my fortune.
One thing to keep in mind about rare runs: it becomes cost-effective to fill up the hold with an A-rank frame shift drive when you're flying a Lakon 6 (which I still can't afford). Most rare producing stations are agricultural economies, which can make it difficult to set up an optimally profitable trade route.
I'm flying the Cobra now. It's better all around at everything, but much more expensive to risk after upgrades. The Viper is slightly cheaper than the Cobra but much better at combat, if you're going to settle down in a system and fight a war.