Hifi, based on what I've READ about the '60SE and my experience with 2 Eleven-As, I'd say they're very close. I THINK the '60SE now uses the same very-high-quality 'styrene coupling and PS-bypass caps as the Eleven (but you might ask c-j), and I've read that it uses the very-same output transformers, and that's why c-j can use 6550s in it.
EL34s in push/pull ultralinear mode, which is how they (and 'most other tubed poweramps that use paired output tubes) are used in the '60, are noted for their uniquely rich-sounding midrange but less-excellent sound at the frequency extremes. In PP-triode mode, one gets even more of that lushness in the midrange, along with less power. The SAME amp with 6550s probably will sound a little less rich in the midrange but a little better in the bass and treble ranges.
I don't know if the '60SE can be wired in triode; again, ask c-j. Ed Deitemeier answers the service@conradjohnson.com e-mails, and he's been very helpful over the years. Whether '34s can be used in the 'SE is another question for c-j.
As far as value, I THINK I'd buy another $1500 used Eleven-A rather than a new or used '60SE, but I've now fallen into the clutches of single-ended triodes, so there's no hope for me!
Good luck. I like c-j stuff and have owned many pieces over the decades.
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