wat are the advantages of the jika rig versus the t-rig carolina rig and jig? is there instances it is better than a t-rig or a jig?

At the basic level, each has its own presentation... each is a different presentation from the other.

If you do a YouTube search on the JIKA RIG, you'll see how that rig puts the weight right under the hook/plastic allowing the bait/plastic to swing freely (unlike a jig) and the plastic actually floats up (if using a floating plastic). I - IMHO - think that it looks very realistic!

You'll also find a couple of different ways to "construct" the JIKA rig... and I believe OWNER makes their own pre-made "JIG RIG"..

I don't have a recommendation as to when to use one over the other. I would think that the Carolina rig would be better on a cleaner bottom... but will let the other more fishing-savy fishermen/women on this forum answer that question. Most will tell you to let the FISH tell you what they want.

I fished the jika rig the other night and caught 6:1 bass to my buddy fishing a Texas rig with the same bait. The very next night I fished the jika rig and got out fished about 3:1.

Just a different presentation. Don't pigeon hole yourself to just 1 like I do most of the time. I do think it is a great way to show the fish something a little different. I would say that the majority of fishermen have never used this technique. Probably going to be real good on high pressure lakes.