Reddit mentions of Cuckoo Sudoku: Sudoku Variants That Will Drive You Batty

I like spirals because its easier to write into a spiral bound (front and back). With you open a paperback the top facing page at the beginning are easy to write in but the bottom facing puzzles are annoying to solve and most of the time bending the spine so the puzzle sits on the back cover usually the Right side of the page is difficult to write in. Spiral Bound puzzle books do not have this problem

For example this review https://www.amazon.com/product-reviews/1454926236/ref=cm_cr_dp_d_cmps_btm?ie=UTF8&reviewerType=all_reviews

https://www.amazon.ca/Loco-Sudoku-Djape/dp/1454916494/ref=sr_1_1?ie=UTF8&qid=1523932634&sr=8-1&keywords=loco+sudoku

https://www.amazon.com/gp/customer-reviews/R2V66ID8NQYZBF/ref=cm_cr_getr_d_rvw_ttl?ie=UTF8&ASIN=140274398X