So I just burned through Tamer books 1-4 and have decided to give them all one review so I'll just copy and paste this for all the books. On the upside, no spoilers since I'll I'll only be talking in generalities.
First, this is a "harem" book, which I know some people are sensitive about. I'm only sensitive about disrespectful portrayals of women and the women involved in this story are aliens so the author is perfectly able to justify the harem based on the women's alien backgrounds. Author also goes out of his way to emphasize the women's other competencies, like intelligence. Still woman after woman seeks admission into the harem and, over the course of four books, it gets a little bizarre and tedious. Personally it would have made more sense to me to have several of the women just not be interested in that type of relationship but so far none seem likely to abstain.
Second, the first couple of books, if memory serves (I did blow right through them) were more along the lines of travel journals. The significance of this this is that travel journals are all about the journey so a big climax isn't required. Books 3 & 4, while still taking the travel journal approach, end on cliff hangers. Books are not tv shows and a cliffhanger in a book either means the author lacks writing ability, wants to milk his readers for extra money or both. The travel journal approach lessens my outrage at such crappy authorship, enough so that I decided to stick with a 4 star rating, but I could definite see how someone would give these books lower ratings.
One of the things the author does well is spread mild humor through out his books. The MC can magically "tame" animals so when he tames a group of five, three male and two female, he names them Scooby, Shaggy, Fred, Velma and Daphne and allows the MC to latter quip about how someone didn't get away with something due to those darn kids, much to the confusion of his alien harem.
One thing that has both good and bad points is that this is a non-standard litRPG. The people aren't playing a game but aliens have given them a HUD that tells them their strength, etc. But no one knows the rules so no one is strategically leveling up. It gets pretty annoying to have the main character repeatedly say throughout four books that he doesn't even know how his tamer ability works. However, without that aspect the characters focus on day to day survival and so it gives the story a real "Swiss Family Robinson" vibe that I enjoyed.
Bottom line: This book won't be for everyone, even litRPG fans, but it is better than a lot in this genre. It is just too bad the author doesn't understand that books are not meant to have cliffhanger endings.