I saw your post, I surely did but I fail to comprehend...speed is always and will be within time. Reaching a point in place regards to a set point of the portal isn't the same. Moving near to or instant isn't helping the fact the portal won't be in the same place as so. Speed of light is nothing to instant, for we can't comprehend it measure it for it's technologically infinitely faster than anything we'll ever grade. So it's left as Instant. The disadvantages, we'll just go ahead and ignore that. (;_There is nothing special about supersonic speed. If we were talking about the speed of light, then that'd be really hax since it could also grant the ability to stop or slow down time. And you could basically reach to any location in the same amount of time you could do with a S/T portal, or even faster. But that's not the case here.
And high speed has its disadvantages i.e. great amount of strain on the body, while the portal power has not shown to take any significant toll on your body. Going by the potential capability of both those powers, I think portal still comes out on top. Because that gives a large amount of versatility and functionality.
If the two are pitted against each other, then portal again dominates. Not because it'll overpower super speed in any regard (because frankly, supersonic speed can hold up against portal transportation) but the portal user will take advantage of the speed user's weakness to eventually own him.
With a portal, you can track someone and reach them at any location, so it'll be useless to use their speed to waste energy to escape. And then you can use the creativity, versatility and functionality of the portal technique (like black hole creation, white hole attacks, deflection etc. there's just too much going on) to force the speed user to use his speed and eventually render him weakened. If he doesn't, then he'll get victimized by the hax techs.
Portal being versatile is all dependent of the user, which happens to also be the same with speed. You didn't state why portal dominates...let's say their like gods and they have not a weakness in terms to their psychic. Please go more in detail with, what ways the portal abilities could do to win...I've started to view speedster winning this as not only does the speedster become instantly able to be any where-matter founded they're also physically at a level being fast with everything...while the portal's master is simply a god without reactions of 'instant speed' so...>.< yeah. GL