Down here in sleepy hollow we use MAESTRO for Brisbane Sydney and Melbourne; with plans to roll out to other locations as/when needed.
It's a bit cumbersome at times; but it does give us a reasonably accurate 'tactical' display of the sequence. It's capable of calculating SIMOPS, Crossing runways or parallels, optimising flows when using parallels etc.
It attempts to share delays across TMA and Enroute; the first minute of calculated delay gets assigned to TMA, the next two to Enroute, the next back to TMA for one more minute then all the rest back to Enroute.
A one minute dalay would be TMA only.
A two-four minute dalay would be TMA and Enroute sharing equally (sort of)
A five or more minute delay the bulk of the delay would be done by enroute.
These of course do vary depending on runway set-up / configuration etc.
Still it needs one flow to manipulate it; where we used to have one flow 'picking the sequence'. Often there was more 'logically decisions' to the traffic sequence before MAESTRO; i.e. wake turb considered against acceptance rate; also when it optimises it just simply gets it wrong and needs manual overridding.
The best thing about MAESTROis that there is no longer sudden unexpected holding (excluding aerodrome emergencies) you can see it coming; it even gives us clues as to when to start holding, blue colours for speed and vectors, yellow for holding...
We can get in as early as 400+ miles from touch and start 'tactical' sequencing; of course if you do get in too early the configuration will change and/or the acceptance rate; thus the sequence will change dramatically and you've caused problems not solved them.
Other major problem with it is Sydney; MAESTRO says give 5 minute delay in enroute (2 inside TMA); you achieve 4.5 of that delay and hand off to Approach who say track DCT outermarker increase speed... This happens a lot because the 'acceptance rate' is lower than is being achieved. This often happens because of the 'political' limitation of 80 movements an hour yet on some configs 120+ would be achievable... I think it looks very unprofessional when enroute are acheiving the delays and slowing everything to have approach speed them up and track direct; but hey that is the system...