Don't get overly hung up with the Macro label on a zoom lens. Look for a lens that delivers a good and balanced optical performance as it makes a whole lot of difference with the quality of images that come out straight from the camera.
Post processing can reduce some lens faults but can't add detail that the lens doesn't first resolve.
Here's an uncropped close-up from the Tamron. Pretty decent close-up but notice that the berries still aren't really bitingly sharp (and this image has some sharpening applied) even with the camera on a monopod.
Contrast that with an uncropped shot from the DA 55-300mm at 300mm. OK it's a boring shot of a dog but look at the fur detail.
Sharp in the center and at the edges, remarkable performance for a consumer grade tele zoom.
There's some light fall-off at the edges but that can be fixed during PP or better still, invest in a proper 300mm prime lens for even better picture quality. :sweat:
At the end, you get what you pay for. Why the DA 55-300mm gets a lot of thumbs up from users is the more than decent performance for the money, especially at the long end.
Of course a dedicated 300mm prime lens will trump it but then we're talking more serious money territory.
I think more people have memories of ugly PF than the macro capabilities of the Tamron, which should already tell you which lens is the more capable of the two.
If you want to dabble in macro, there are plenty of options, from investing in a proper macro lens to using extension tubes, close-up filters to an old prime lens or even reversing the lens itself.
With such an approach, you'll get far better macro results than the so-called macro from a tele-zoom.
Ditch the Tamron and start saving for the DA... but hey, it's your money.