Always do your homework beforehand. Just like when you're buying a product or a service you want to see what previous experience others have had before you. This forum is awesome for that because so many people share their experiences with a certain publisher or agent so you have a general idea of what to expect before dipping into the pool. Same thing with shared bad experiences with scam artists.
As for people who actually like your work, it can be hard at first to decipher true blue enthusiasm from the mere niceties of being brushed off and rejected. From my experience, I benefit a lot of my fellow writers (and some discerning readers) whom I know and trust to give me critical feedback to better my work. The business is filled with a lot of sharks so it's vital to have a nice network of authors to go to for venting (after those rejections), celebrating (after those acceptances and milestones) and most of all for support (for all the other stuff).
Either way, focus on telling the best story you can and never lose sight of your vision and goals for your writing.
