It really depends on what you mean by “competitive point of view.”
In a 5stack vs 5stack with both teams on VOIP, Sawbonez is built to pocket the Primary DPS. To that end, you want perks that help you in that role, which is slinging lead with your Fragger and keeping him up. With this mindset, the CR42g1 is my loadout of choice. (Mine comes with added stylepoints.)
http://images.akamai.steamusercontent.com/ugc/94979810852370129/EDD7C209904C9B76A88A7A05F26355177A3B4527/
Potent Packs keeps you alive, which keeps your Fragger alive. Drilled is great for lobbing packs to yourself and your Fragger and still getting bullets in your gun to not get caught with your pants down. Focus helps when getting shot, which will probably happen a lot on the frontlines.
The SM41g2 is also excellent for the pocket role, as it has Drilled and Potent Packs, along with Bomb Squad. You miss out on Focus, but have a primary with lower spread, so aimpunch won’t be as much of a factor. (The perks listed in the original post at time of writing are for the SM72g2.)
If you are playing in a less coordinated environment, or are running Sawbonez as a solo or field medic, your priorities should change. Your entire team needs you, rather than just the primary DPS. You should still throw lead, but probably avoid taking as much as possible, looking after your team more. With this mindset, the SM72g2 stands out. Extra Supplies is borderline essential, since you could need to sustain 2-3 teammates and yourself. Get Up means you get more out of your defibs, saving packs and/or allowing you to move onto the next patient/victim faster. Untrackable helps keep you alive, but isn’t as powerful as the other perks.
The CR81g2 can also fill in that role, with Extra Supplies keeping the team alive and Bomb Squad and Unshakeable keeping you alive. It’s not as support oriented, but if you prefer the Crotzni, it’s an option.
I absolutely love the Blishlok, but I don’t see loadouts with it having a place in ranked/competitive. The BL71g2 can fill either of the roles above, but not nearly as well as the other loadouts, due to the nature of the Blishlok. It is better at further ranges than the other SMGs, but isn’t as useful in the close-mid range engagements Sawbonez will normally be in, because of the lower rate of fire.