You might wait for people who used both. Most people I believe use 1 of them.
I don't want to judge in favor one product or another, but you can do comparison by using Search function of this forum.
Do "enthuware" keyword search first, then "whizlabs" and you may have own opinion after that.
Exam 1Z0-810: Upgrade to Java SE 8 Programmer Study Guide and Quiz Exam 1Z0-817: Upgrade OCP Java 6, 7 and 8 to Java SE 11 Developer Study Guide and Quiz
I think most people use Enthuware; I only used Whizlabs (and Sybex) and it was good enough, don't know if better or worse than Enthuware. Whizlabs also has an online course which (for OCA 8) was quite rubbish IMHO, I got it for free so it was ok but not it's worth paying extra.