You should explore all the skills to see what you like best. There is no real "best" combination.
However, pure skill builds are struggling to match the performance of pure shooting builds at the very top end of the game. That's like the very last 5% at the highest difficulty. Until then you can play literally anything. So I highly recommend you try everything out.
The only gun that's truly head and shoulders above anything else is the Classic M1A Rifle. It's likely to get brought back into line with the balance pass near the end of may/beginning of june. But right now it's REALLY good. Some prefer the Military Mk17, and I agree that it's mostly a stylistic choice: Larger mag with higher RoF and less damage per round, or hard hitting slower shots with a smaller mag.
I strongly suggest you learn the ropes with at least one of each type of build: Weapon Damage(red) / Armor(blue) / Skills(yellow).
All red builds are very popular right now, and for solo will often use a revive hive and a fixer drone or crusader shield for survivability, sometimes with a chest piece using the talent "Unbreakable" for those moments that you screw up.
Blue builds using a Bulwark Shield and pistol are very common as well. Although the crusader shield is decent for DPS builds, it's not very good for tankier blue builds until you get the artificer hive.
Yellow builds are tricky to learn, but can be VERY powerful once you get the gear to support it. Although to be blunt, they're not generally solo-friendly, and work better in a team.
Getting to level 30 and using specializations and set gear should probably be your first goal. Once you've played around with those for awhile you'll have a better understanding of what style of play you enjoy most, and can make a better decision of where to go from there.
1 people found this helpful