Hello Nicolai
I did my first Try Dive on Rebreather back in November and in was on an Evolution.
Before the dive, my thought process was much the same as yours and I was expecting to be anti-climatic, if that's what it is to be.
But in my case, I loved it I got the hang of it within 5 minutes.
On that dive I learnt a lot, I have got to comprehend a lot of things.
Since then I have tried the Optima and Prism.
Configuration and trim, I grant you from my perspective is important, just as other things.
I am looking at making the decision in getting a Rebreather in a month, sfter I have tried the Meg.
Part of the process for me is to see which is the most comfortable in the configuration that is given to me on the day, so far, different configurations have taken some to adjust to, but I can see whatever unit I get, I will have start adjusting for my person.
Here is a thread that I started, I am hoping in a couple of postings to announce my decision.
http://www.rebreatherworld.com/intro...r-journey.html
You said you had a cold couple of days ago, I would say you didn't recover fully and that added to angst of the dive.
I can only say, do not give up here, try it again and try other units as well.
Keep Going and do not quit.
Good Luck