I agree 100% with what you said, that's why demo periods are great. In case of Boz I expressed a quick opinion, where I said that it was a great tool, but preferred Nebula in that certain instance. Never said it was not a good plugin. Of course, after trying it more especially due to David's comments, I found it performed better than Nebula on other sources. I bought it in the end.
In the case of Essence I as well still think it is a superb plugin that might be the best in a certain situation, like it was with something I worked on yesterday. It is just that sometimes you forgot about certain tool you already have, because you didn't use it in the last 15 projects for example. And after you are trying something new, that provides the quality and complexity of DMG Audio products, you rediscover it. You maybe wouldn't think to use it in a certain situation, but after you do, you realize its strengths. And this happened in this case.
If I didn't have Fabfilter and Sonnox, I would definitely go for Essence. But in this case I still prefer what each of these tools do on the sources I tried them on (of course there can be the case where Essence would totally win over the aforementioned tools). What is also true is that I haven't used my Sonnox Supresser for nearly a year now...not because it wouldn't be good, but because I used something else that came on my mind and did the job and was probably more intuitive. Before spending money for another tool I then "kind of rediscovered" Sonnox Supresser and will probably use it more in the next projects...and probably on things I didn't use it before. So this is what I like about demos.
Nearly two months ago I again started using Sonnox EQ as my main eq over Fabfilter and EQuilibrium. I put it to ears only mode without a graph and found out I achieve better results in quicker time like this...and this is what it is all about in the end
After I finish work or early in the morning I like to read the news on this forum. I will try to not post my intermediate impressions, but will rather post opinion after a month of use. But with other developers apart from Steven Slate it is basically impossible to do this, because it looks like ressurecting an old thread

Aside from that I love new technology and despite already having all the tools one might need I like to try out new ones. Some turn out to fire just initial excitement because they are new, some of them I don't like at all, others grow on you after time. This last ones are usually the one that gets purchased and used the most in the end.
Of course I still think that Dave's tools are together with Fabfilter's offerings some of the best bread and butter tools available today. But when I have to use subtractive EQ for notching I still prefer to use Waves Q10 for example...and if I am correct this is the first plugin parametric EQ in history