So far I've been using the Clipboard Manager (CM) in Alfred 4 and was mostly happy with that, and greatly preferred it over what BTT when I last compared them (which was some time ago -- maybe 1-2 years?)
But today I saw the BTT 4.9999 release notes which mentions many interesting updates to its CM, so I thought should give it another try. And I really like what I am saying, and am considering to switch now.
That said, I run into some issues / miss some bits. Note that I am running macOS 12.7.6 (21H1320), on an M1 MacBook Pro.
1. A feature request
I have one feature request / request to get a hint how to achieve it: in Alfred, when I select an entry in the CM and press return, it does not paste it but rather just puts it into the pasteboard, and also moves the selected entry to the top of the list.
I am really used to that and prefer it over direct pasting. I saw the setting to select different "standard" actions, but "copy & move to top" is not in there?
Moreover, "just copy" and "copy & move to top" do not seem to count an "action": I have "close after all actions" enabled (see screenshot) but "just copy" and "copy & move to top" don't close the CM. Would love to have that 
2. Glitch with CM settings
I also run into a bunch of glitches: just now the CM settings stopped working (if I click on the little "wheel" icon nothing happens). Restarting BTT fixed it. While typing this message, it happened again... Possibly relevant: the tooltip of the "gear" icon looks as if it is "active", see screenshot:
Aha, I think I found a way to reproduce it, and I think the "Close CM on outside click" setting is relevant:
- open CM, click gear icon, this opens the settings
- click outside CM window to make it close
Now the "gear" icon is broken, with all the issues described above.
I can workaround it by closing the settings by clicking outside of them but inside the CM window, so that it stays open. Then I can click outside of the CM window to close it, and all is fine.
... and while I am typing this post, I realize a similar issue affects the circle-with-three-dots icon in the lower right: if the popup menu this button opens is active and I then click outside the CM window to close it, then afterwards this button is broken for me (I think I restarted BTT half a dozen times by now just while typing this post 
)
3. CM did not go away at some point until restarting BTT
Earlier, when I switched the "Close CM ..." settings as in my screenshot, the CM did not go away anymore at all. Even after changing the settings back. Had to restart BTT, then it worked fine. I guess I can try reproducing it if desired.
4. Some minor suggestions
better tooltip text would be great:
- the "As One Line" button has the tooltip "As One Line" -- perhaps it could say something like "Paste as one line, replacing each line break by a single space"
- the icons in the top row (including the "gear" icon, the "pin" icon etc.) all seem to have the same tooltip "Toggle Collapse" ???
- the pop up menu in the top right seems to be about selecting the format -- great, perhaps a tooltip could say that
- the top entries in the CM list have little numbers-in-circles next to them -- what do those mean? Perhaps they hint at some way to quickly choose these items with some hotkey? No way to tell, a tooltip for them could explain it?
I also have questions about keyboard navigation when the left & right side "extensions" are shown as here:
- how can I navigate the list in the "left drawer" (see screenshot) with my keyboard? Even if e.g. "All Items" in that list is selected, pressing up/down arrow key instead moves the focus to the list of clipboard items and then moves up/down there.
- perhaps there is already key combo to achieve this, but how would I ever discover it?
- what I would expect to work "intuitively": if "All items" (or anything else in the "left drawer") is selected, up/down navigates there
- then "right arrow" would move the "focus" back to the list of clipboard items
- and pressing "left arrow" in that list could move the focus to the "left drawer" (at least if it is expanded; if it is not, then either do nothing; or else perhaps even expand the drawer?)
- The above suggestions would fit with what happens if I press "right arrow" on text clipboard item (at least when the "right drawer" is expanded): the focus moves to the right drawer and one can edit the clipboard item (BTW that's a pretty cool feature!).
- but there I also have a question: how can I navigate back from there if I pressed "right arrow" by accident? Right now I have to resort to my mouse / track pad
- suggestion: allow something like Cmd-Left Arrow to move back (and then for symmetry also allow Cmd-Right Arrow to move from the clipboard items to the "right drawer")
In closing, thank you very much for BTT, it is wonderful.