[Cinisajoy]

Please and thank you are not the same. Please is asking for help. Thank you is for after you get the help.
If you want to use thank you the way you did, say thank you in advance.

Since you asked, no your OP does not seem reasonable or nice.

Your English in itself is pretty good. The phrasing on the other hand needs work.

I can translate how most people read your first post.
I am looking for a new ereader. Give me very long and detailed answers on what you think of each company so I don't have to do any work myself.
It came across as being told what to do, not asking for opinions. Comprehensive review is a very bad choice of words.

If I was going to ask for help, the first thing I would do is see if there are sub forums dedicated to the company and read the stuff there. Then I would start a thread that read something like this.
"Hi. I am in the market for a new ereader. I have been reading the forums and would like your opinions on the following companies (list of companies still interested in) if you have dealt with them. Thank you in advance."

Hope this helps.
I just wanted to add English is a difficult language. On another site, we are forever having English to English problems.