I am also engaging in one of my occasional searches for  a better email  setup.    I only learned about eMclient  week or so ago,  and I'm trying to determine if it's worth the hassle of installing an evaluation copy.   ... Oh heck,  since I just learned that eMclient > 8.3 tags  or proper interface to Gmail labels,  I just  installed the evaluation copy  of eMclient ...

My biggest complaints with Outlook and Thunderbird are:

No unified inbox  in Outlook.  Thunderbird wins there. I see that eMclient supports unified inbox. Q: does  eMclient also support unified  Drafts/Sent/Trash/... /Trash  the way Thunderbird does?   I cannot tell from their screenshots.  ... Now that I've installed the evaluation copy, I can see that eMclient only supports unified inbox, and does not unify the other things.

Treatment of Gmail labels - the IMAP folder kluge.   Outlook scores worst here,  and Thunderbird only a little bit better (because of the gmailbuttons add-on). I suspect that  all or most  IMAP clients are similarly handicapped,  although I would love to find a client that supports adding the X-GM-LABELS headers  as well as  full logic and/or/not queries using any header. Q:  does eMclient just support the IMAP folder kluge for Gmail labels,  or does it have anything better like Gmail buttons or even X-GM-LABELS? ...  So I googled a bit more and found https://forum.emclient.com/t/categories-in-em-client/73942 ... It looks like eMclient tags may correspond to Gmail labels, since EMclient 8.3.   folders or just an alternate UI  for tags/labels. This  will be enough for me to try eMclient.    hallelujah!  ...  it may be enough for me to buy eMclient.

Other IMAP state:   although both Outlook has flags and categories, and Thunderbird has stars and tags, none of these are properly supported  when running with a Gmail server,  except for a plain Jane flag.   AFAICT the only orthogonal  message properties supported by the intersection Outlook&Gmail or  Thunderbird & Gmail are read/unread and flagged/unflagged.   I think this is again probably a limitation of  the Gmail IMAP interface, but  I can hope: Q: does  eMclient  on top of Gmail support  any additional orthogonal message properties other than read/unread and flagged/unflagged? ...  AFAICT no, eMclient only supports  ordinary flag which corresponds to Gmail ordinary star - yellow star - and not any of the colored stars or other marks the Gmail supports.   nevertheless, proper orthogonal support for tags/labels  Is a big win.    now if only I can dictate/label paths to  eMclient.

Petty -  I use Move/Copy Message to Folder a lot.    I would really like the folder picker  to have the option of accepting a folder path that I could  utter directly, or have a  speech command insert.  Both Outlook and Thunderbird have a picture that has no text box input.  while it can be navigated  a folder name at a time,  I have found it fragile and error-prone.  Enough so that I've written my own VBA code doing stuff like  myNameSpace.Folders("xxx@gmail.com").Folders("Defer").Folders("Someday"), and, yes, parsing string older paths.  nevertheless it would be nice to have a better folder picker -  I have been meaning to post about this for a while.  Q: what does eMclient's move/copy to folder picker look like?   can it accept a folder path  direct from speech, or do you have to pause at each level?   I guess does it look more like  the Windows Explorer filesystem browser than it does the Outlook  folder picker? ... EMclient's copy/move  folder supports a text search box to filter folders. However, it has even worse navigation by folder name than Outlook does :-(  The  alternative tag interface at least supports  Gmail's /- separated label hierarchy, but OMG  it is slow,  at least with my legacy of many many Gmail labels... :-(   ... Frown, So far I have not been able to dictate  folders/labels/tags like Defer/Soon or Defer/Later to  eMclient,  something that I can do  in Outlook albeit not very reliably

The main reason that I have found dictating anywhere in any application triggering random commands has been when the application has hotkeys or  keyboard shortcuts that use ordinary unmodified printable keys. E.g.  Thunderbird using "A" for archive - not ctl-A, not alt-A, just plain old letter A.

Thunderbird is just horrible  in this regard,  as are many  emacs modes.    I have not had too much trouble with Outlook  ---   have you?

(Ah, yes:  the biggest  problem I have with dictating anywhere in the Outlook Windows is that {space}  scrolls down the current message and onto the next at end.)

Anyway, eMclient seems to have a pretty basic  set of keyboard shortcuts, no printable unmodified keyboard shortcuts by default. :-)

I am not that happy with eMclient's keyboard accelerators.   they have the classic problem where the same letter is used more than once in the same menu, e.g. {alt}{s} => settings, {alt}{s}{s} => messages.   tolerable if there's some guarantee that it won't change, but usually this approach breaks,  e.g. you might have to press {s} three times to  get to messages   depending on dynamic menu items,  or in some future version.

So far  it seems to me that eMclient  is not completely friendly or amenable to being keyboard driven, and hence may be hard to automate completely in speech commands.  Some things like highlighting text (background color) appear hard to obtain from the keyboard in eMclient.

I am not yet 100% sold,  and I fear, like the OP,  that this will just be another email client that I try for a few days and run into lots of problems.   But it's the first PC client I found that supports Gmail labels properly.

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Later: eMclient has very limited search logic.  Apparently it cannot do a query such as "search for messages that are Unread or Flagged or in folder:Defer1 or in folder:Defer2 

Can always do that in Gmail.  Except Gmail doesn't really support saved search folders, except by saving URL.

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