Whatever you get make sure it has direct drive, where the drum is turned by magnets rather than using a band. It's the biggest change in washing machines in the last ~10 years and supposed to result in much less wear and tear.
The self-dosing ones seem to annoy people so I'd probably steer clear of those.
Apps are pointless IMO. It was useful for the first month or so to find out the energy use of the cycles I mainly use. We moved house and I never bothered to reconnect it to the wifi. You can download all these extra cycles, but it replaces the rinse + spin cycle 
and none of them seem to do anything that useful.
Agree it is good to be able to pick the spin speed, temp and ideally a button to shorten a cycle is helpful too. The latter is the only thing my new machine doesn't have and I miss it.
The cycles I tend to use are these:
Quick 15 min wash (but I increase spin speed and it actually takes 25 or so mins) - if I have a few things that I need to wash separately, or DS1 (16) tends to use this as he doesn't have many clothes to wash at once.
30C or 40C normal cottons wash (~1hr)
Longer, 40C eco wash when not in a rush (~3hr but less energy use overall)
60C/90C cottons wash (~90 min) - for cleaning cloths, bedding, face cloths etc.
- Prewash (adds about 20 mins) - when I want to rinse first or put different cleaners in the different wash parts.
- Intensive (adds about 15 mins) - when clothes seem especially dirty.
Mine has a specific drum clean cycle but not sure what it does differently. With the previous machine I would just run a 95C cycle to clean it.
It also has a duvet wash cycle which is one of the main reasons why I bought it but I'll be honest, I haven't been brave enough to use this yet! I think washing a duvet in our old machine might have been what started to kill it as it was never the same after that, it unbalanced it and then eventually refused to spin at all.
Large drum size is beneficial, as long as it doesn't make the machine itself too big.
Agree a pause/add item button is also helpful.