We found these, and loved them so much that not only did we buy one of each set, we became resellers.
They are 100% compatible with LEGO brand blocks. As far as quality goes, they are as good as you can get – we collect the name brand, and would not sell these if we felt they were a poor value.
There is a representative sample of the assembly instructions pictured; they are quite easy to follow.
Rex is 6.25" long x 4" high x 2" wide, 152 pieces, and comes with 2 minifigs
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