If you play more defensive turrets are best.  If he beams them in the first 3-5 min to PoR player just destroyed his eco so just keep putting turrets up and pump out flamers or counters to whatever he is making(if he continues to linger at your base).  Hogs are are tricky vs good Covenant players since they have lots of counters, plus cost the UNSC player quite a lot early game to get gunner and pump out 5+ hogs(except Forge).  If you watch good UNSC players that go hogs usually have insane micro to keep the hogs alive so they get the most out of their investment.  Im telling you though most top page PoR players know you are going to hog rush with 3-5 hogs early game and prepare so you will get nowhere fast then they just push back 3-5 min in and demolish you before you can get anything else up.  Plus if you hog rush 9 times out of 10 you wont have turrets up or only have 1 maybe maybe 2.  If you manage to get turrets then you have NO units and it is an easy win.    

If you are Covenant, shield is most important unless you are going insane offense.  If you are just doing a standard opening build then you want a shield decently fast especially if you are being rushed.  Scout as always and know what is happening.  GET HOOKS.  Get the supply elevators first because these give you the most advantage early game.   Jackals are worthless to attack a base with unless accompanied by a unit with a lot of building damage like a locus or hunters.  A good PoR player can kill 25+ jackals without losing the base shield because I have done this in a game before vs Betray Me and I have won a game vs WolF because he didn't have anything that could do building damage and it took them both over a minute to get my shield off my base and I had crippled them while they were trying to kill my shield.  

So to re-cap....Shield for Covenant and Turrets for UNSC is your best bet.