I find it to work quite well. I also use it with ActionsApp for iPad (soon to be Quadro) – and it always performs consistently.
Essentially, the steps would be as follows:
1.) I invoke Shortcat app. I type “.” – which forces Shortcat to highlight all the possible UI elements it can interact with on the screen. It then overlays a short letter-combo over each UI element, such as AA, AB, AC etc. – depending on how many there are. [The alternative procedure would be to invoke Shortcat, and start typing the name of the button – i.e. like “next” if there is one down below, on a forum page – the actual button will then be highlighted].
2.) Once I “see” that the correct element is selected (it gets highlighted in blue) – you simply hit enter. If you start with “.” instead, which throws up the overlay, and several UI elements are selected, you simply use CTRL+AB (or whatever the relevant overlay letter combo is) to select the correct UI element, and then hit Enter – whatever is quicker.
3.) Having noted what letter-combo activates the relevant UI element – or, what combo of letters I can type (e.g. “next”) to have that UI element selected, I then simply get KM to do this for me.
4.) So KM invokes Shortcat by calling up its search–bar with its keyboard shortcut (like one could use KM to invoke Alfred), then [types] “next” (or “.” and CTRL+AE) to have Shortcat select the correct UI element, and then hits ENTER to “press” it.
Basically, KM simply does what I would have done manually – I simply do it the first time, to check what I would need to do in that particular programme or whatever.
By way of example, in one of my frequently used programmes, the various search functions had keyboard combos for advanced search, or text search, or group search etc. But there was no keyboard combo for getting the cursor into the “quick-search” field of the main window. I use the latter far more frequently than the others.
So I’m inside Scrivener or Devonthink – I select text, invoke KM – which copies the selection to my clipboard, jumps over to the other App, invokes Shortcat to run the UI search, selects the Quick-search window UI element, hits enter – which places the cursor into the Quick-search field, then pastes the clipboard, and hits enter again to invoke the search.
Without Shortcat in the middle, I couldn’t get “into” the Quicksearch field, in the absence of some UI script. And all the above happens in split seconds, to the point of not being noticeable…
Apologies for the lengthy off-track explanation, but hopefully that explains things properly…