Sort of 2.5 stars? I appreciate having the testing engine with it, but I found the topics felt skimmed over, and I fear this isn't just a feeling on my side. RSTP is covered in an appendix only, VRRP gets a passing mention... I found the ICND1 book much more useful by comparison, in that it taught me much, much more (I started from basically nothing, except knowing what ipconfig /all was).
I advise completing this one with other materials and with blank exams (like VCE ones).