This year I am using 5oz cups for vegetables and flower seedlings. I used them last year for some succulents that I wanted to share for fundraising and they turned out great since it made transport so much easier. I also I did not have to lose a bunch of my 4" pots that I need for transplanting and hardening off.
So far, everything seems to be working well, despite the weather changes. They do require some daily attention however to make sure they get the water they need and some sun. I have them outside in a converted dog kennel, now my happy place AKA greenhouse.
What do you think? Have you tried this?