Great comparo. So I guess you won't be giving up your XO 5 anytime soon? Same here. I have the XO 5 and 2.5. I don't see them leaving me in the foreseeable future.
I haven't done a direct comparison between the XO's and other 5 or 2.5mm eyepieces. But from my direct observations of Jupiter and double stars, I'm confident that the XO's are excellent planet and double stars eyepieces.
So far I've been most impressed with the XO's performance on double stars, even though I'm not really a double star enthusiast. According to my own personal interests, doubles are below DSO, planets and the Moon. That's just the way it is. But since seeing the Pup star recently for the first time - and that was through the XO's - my interests might shift more toward the doubles.
[From Gene's comparo:] Sirus was up, so I put both eyepieces on this gem. Again, both eyepieces performed superbly. The 5XO is going to make a nice double star eyepiece.
I wish you would have gone into more detail in this comparison of the two eyepieces on Sirius. So you did see the Pup through both the Delos 6 and the XO 5? How did the view look in each eyepiece?
In my 10" f/4.8 Dob, I could not tease out the Pup with a BGO 7 (171x) or 6mm (200x). The seeing and transparency that night were at least 4/5. Maybe there was too much scatter in the BGO's or the spider spikes were too prominent for those magnifications. In any case, as soon as I put in the XO 5 (235x), the Pup star was obvious. A good, clean split. But Sirius B was a beautiful sight in the XO 2.5: a crystal clear image at 456x, 47x per inch! The Pup was a sharp, light-steel-blue point between two sparkling spikes of Sirius. Caught the Pup for the First Time
For my eyes, I did not find either XO uncomfortable. Yes, they have short eye relief. So I had to take off my glasses to view through them. No big deal. That's why I keep my glasses on strings. Also, the relatively narrow 44 degree AFOV and high power did not bother me. My Dob does not have tracking, but I can nudge with the best of them. That's no problem. My mount is well balanced and has smooth motion. The superb view was worth any of these minor inconveniences.
No, I don't think I'll be giving up these XO's anytime soon, either. I believe there will always be a place in my
equipment case for both XO's!