so a Uniden would be better?
Unidens DMR/NXDN trunk tracking works best when there's a lot of channels occupied with calls at the same time. Whistlers work better when there's less activity or with very busy systems using fewer channels.
Trunked systems are designed to have radios sitting constantly at the control channel, not scanning them as scanners do, so there will be some problems using scanners. Scanning the actual voice channels when there's activity on them will often work better. Whistler wouldn't have been able to sell as many scanners as they have if it didn't work as well as it does.
Uniden haven't optimised their DMR decoding and when verifying using an actual DMR radio a Whistler works perfect where a Uniden scanner doesn't catch all the calls. My impression are that Unidens P25 decoding are working perfect but that Whistler struggles a bit. That's why they have adjustable settings for ADC and DSP to try and correct that.
There's no single scanner that can do everything perfect, you'll need to have several different brands and use them where they work at their best, or you will have to accept that there will be some flaws.
/Ubbe