I don't usually have a lot to say about headphone plugs, but the XBA-4's right angle, 3.5mm, gold-plated plug is finished in glossy black and chrome and exudes class. The XBA-4 doesn't come with an inline microphone or a remote to control Apple devices; if these features are important to you, you can pick up the XBA-4iP for $20 more.
The headphone does, however, come with four sizes of silicone eartips and three sizes of noise-isolating tips. The "L" and "R" markings on the earpieces are fairly small and will be difficult to see in low-light conditions, but you should be able to find an appropriate size for your ear canal among the seven options. Achieving a proper seal is important to getting the best sound and the most isolation out of your headphones. Finally, Sony also includes a soft faux-leather travel case in the box.
The XBA-4 is a superb-sounding pair of headphones -- they offer a keenly balanced mix of deep bass, a natural-sounding midrange, and smooth treble detail. The ultimate test of any headphones is how they sound after long listening sessions, and the XBA-4s never left me fatigued. Beyond the sound, the earbuds are comfortable to use as well, though I was aware of the bulk of the relatively large earpieces hanging off my ears. That said, they felt secure, and never fell out without a significant tug. The cable was free of "microphonics," meaning it doesn't transmit any sound when it rubbed against my clothes. Finally, heavy distortion and loud volumes pose no challenge to the XBA-4s, and I found myself playing music at deafening volumes without fear of distortion.
I compared the XBA-4s to the Etymotic ER-4PT (single balanced armature) in-ears for contrast -- the XBA-4s presented a richer, fuller tonal balance with a more powerful dynamic slam with well-recorded drums, while the ER-4PTs gave off a brighter sound and superior resolution of fine details. On the other hand, I actually prefer the way the ER-4PTs reproduced the snare drums attack and the cymbals' sizzle. They're both good, but I felt the XBA-4s prevailed with a more accurate and refined sound.
I also compared the XBA-4 headphones with the Audeo PFE 132 in-ear (single balanced armature) headphones. The XBA-4s had better bass and came off more dynamic and noticeably fuller-sounding than the PFE-132s. Additionally, the acoustic guitars sounded more realistic using the PFE-132s, with the XBA-4s blurring the sound of each note together.
All of the above listening tests were conducted with my iPod Classic, but I also used the headphones to watch a few movies on my computer. Paired with a FiiO E17 headphone amplifier, the XBA-4s sound even more spacious than with music, and add a deeper audio layer to the theater experience.
Sony's first foray in audiophile-quality, balanced armature headphone design is largely successful, and the XBA-4s sound excellent -- if you can swallow the price tag, you'll enjoy their sexy design and rich sound.