There have been some operational issues:
* communication between 25k COM and 8k33 COM show the expected mismatch, i.e. a 25k COM transmission on FFF.F00 is often unreadable from a 8k33 COM at FFF.F05, although the same physical frequency
* ground stations changing to 8k33 frequencies frequently forget to give notice to FIS, thank to GDPR no automatic notice is given from the ITU authority to AIS and FIS, so fields have to actively give notice
* airfields still struggle with handhelds, forgot to buy 8k33 ones and find out by 'surprise'
* the not synchronized timing on when to go to 8k33 last year was the biggest sh*tty mess I ever saw
* 8k33 radios are usually modern digital devices with a lot of modes, menus, complex usability and not every old fart appears to be capable to deal with
* unpleasant surprise: Garmins older 4xx/5xx 8k33 capable GNSS/NAV/COM cannot store 8k33 frequencies, so the lookup of frequencies from the GPS is broken, wonder what they paid to get a 8k33 radio not capable to store 8k33 frequencies certified, upon complaint they say it is a database issue they are not willing to fix - cut purse behavior, drives more people to Avidyne though