I've tried both the regular wire-free Show-Off and this underwired Show-Off, and the difference is so huge that I can't believe Champion used the Show-Off name for both.  The regular Show-Off is not a bad bra, and is fairly comfortable to pull on over the head, although it runs small despite coming in simple (S-XL) sizing.  In comparison, this underwire Show-Off, which comes in bra cup sizing, runs ridiculously small, and is hands-down the MOST uncomfortable bra I have ever tried to wrestle over my head, in my life, bar none.

The difference between the two bras is like night and day.  The regular wire-free bra is a nice matte swimsuit-type fabric that is smooth enough to glide over your skin when you pull it on.  The underwire Show-Off is a rougher, coarser fabric, and it has a lot less stretch to it, which makes it much more uncomfortable to wear.  Specifically, the band that goes around your upper ribcage is so rigid, that it's almost impossible to fasten behind you.  It's extremely uncomfortable.  And despite being my normal bra size, the bra was far too small in the cup to be comfortable or practical.

The underwire version does not have a built-in racerback, although it has a hook that you use to transform it into a racerback.  But because the band is so rigid, you can't expect to leave it configured this way while you pull it over your head, because it's impossible.  You'll have to hook and unhook repeatedly anytime you wear this bra.  In comparison, the Wire-Free version has a smooth racerback with stretch, so it's easy to pull on.

If I had to find something positive to say about this bra, it would be that the Show-Off Wired has nice padded shoulder straps, whereas the regular wire-free version does not.  It's also worth noting that the Show-Off Wired is much larger all around than the similar size in the Wire-Free.  The front rise is higher, the sides are higher, and the straps are obviously much larger.

I've attached some photos showing the bras side by side.  The blue is the Show-Off Wired and the black is the Show-Off Wire-Free.