I bought this Quick Reference Guide (QRG) with the PMPOK Guide thinking these ref charts would save time - I think it might be called "Quick" for the reason in the "bad" section below
The good - The publisher did a very nice, quality job on construction and it has well laid out groupings of information (This keeps it from being a 1 star). I really like the idea of a consolidated mix of key terms/vocab next to the Inputs/Tools/Outputs for each section - though the terms don't match the BOK. For fairness, the QRG does NOT say it summarizes the BOK and it DOES say it is for use with the "How to Pass on Your first try" book which I have not seen. That might explain why the QRG brings up a few terms that I did not find in the BOK.
The bad - The I/T/O groups are terribly incomplete - about 30% or more information is missing from each of the BOK's OV sections I looked at (Comms/Risk/Proc Mgt areas). An extreme example is from Id Risks 11.2. The BOK has 11 Inputs the QRG has only 4 Inputs. Which source am I going to trust to reference prior to an exam or during a project? Obviously from my rating, I cannot use this as a standalone guide for reviewing because I am only reviewing partial information and therefore only partially refreshing my memory on the BOK's inputs, tools, outputs across the processes.
The QRG is too low a cost to return and I do like the additional terms, but I do plan on directly referencing the BOK's OVs and DFDs since those give a simple, well laid out and *complete* review with a process-integrated perspective. At least my 3*, $30 Internet reference material set completely lists all 87 I/Os and their 206/129 uses across the 42 processes and the 135 tools etc and includes a colorful 100 page doc on all the sched/cost/qual/EVM formulas.
Bottom line, my study plan does not reserve much time referencing the "Quick" Reference Guide.
A side note. From the $90 I have spent on PMP study material my initial review a lot of hit and miss - 2 docs at 2*, 1 at 3* and 2 are 4* (BOK is good for understanding fundamental data leading to test prep, but has no practice area and is missing a lot of essential information specific for doing actual PM work on development projects, which to be fair, they do acknowledge at various times). It is clear from my initial review that the BOK does need to be supplemented, so my advice is to pick your materials well, based on where your knowledge & experience levels are and how you best learn.