Hello jeanny and welcome to cruise-chat;
first, I seriously doubt if Silversea is so bad that nobody wants to talk about it; it's much more likely that there just aren't very many crew members compared to the mainstream lines; and we hardly ever hear from any of them. Remember, Silversea only has four small ships--ultra luxurious ships (I hear)--but small ships.
Secondly, working on a ship involves long hours--the lines try to get the most out of their employees; so the crew members probably don't have a lot of time to surf the net looking for people interested in what their job is like.
Having said all that, and barring any other information that might convince you otherwise, I would urge you to take advantage of this opportunity that others would die for.
I say this because I took a job with Princess many years ago, almost on a whim, and it was one of the greatest experiences of my life. I had every reason not to go: I was a musician trying to scratch out a living in Los Angeles; I was married with one small child and another on the way; and I had never been on a ship and knew nothing about what was involved.
But I was also, as we like to say, "between engagements" (that's musician code for "out of work"); So I signed up for three months and it turned into a four year gig.
Well, I absolutely fell in love with the sea and with ships. And now, thirty years later, my wife and I cruise as ofter as we can, as passengers now.
So I encourage you to give it a try. It dosen't sound like a long commitment--and it could turn into a lifelong love affair.