Ingestion
Get all answers from MSE discussion in an XML object:
xmlObject =
Import["https://mathematica.stackexchange.com/questions/234881/benchmarking-with-mathematica-v-12-for-up-to-date-comparision-of-mathematica-acr/235384#235384", "XMLObject"];
Get code XML elements:
lsRes1 = Cases[xmlObject, XMLElement["code", {}, code_] :> code, \[Infinity]];
(Note of that at this point code strings are obtained.)
Remove Benchmark
computation commands and convert the code strings into WL code:
lsRes2 = Map[(ToExpression[Map[If[StringQ[#] && SyntaxQ[#], #, Nothing] &, #]] &) @
StringReplace[#, {"LaunchKernels[]" -> "", "BenchmarkReport[]" -> "", "Benchmark[]" -> ""}] &, lsRes1]
Select code (blocks) that are lists of rules:
lsRes3 = Select[Flatten /@ lsRes2, MatchQ[#, {_Rule ..}] && Length[#] > 1 &];
Length[lsRes3]
(*31*)
For each code block flatten the metadata and benchmark results into associations:
lsRes4 = Map[Association@ Cases[Flatten[# /. HoldPattern["Results" -> r_] :> (Rule @@@ r)], _Rule] &, lsRes3];
Length[lsRes4]
(*31*)
Make sure all associations have the same keys:
lsRes5 =
Block[{lsAllKeys = Union[Flatten[Keys /@ lsRes4]]},
Map[Join[AssociationThread[lsAllKeys, "NA"], #] &, lsRes4]
];
Length[lsRes5]
(*31*)
(Otherwise, the obtained dataset might be hard to use in some computations.)
Make a comparison dataset:
dsBenchmarks = Dataset[lsRes5];
dsBenchmarks = dsBenchmarks[SortBy[#BenchmarkResult &]]

Basic analysis
Summarize the dataset:
ResourceFunction["RecordsSummary"][dsBenchmarks]

(Bar) plot results:
Multicolumn@
KeyValueMap[
If[VectorQ[DeleteCases[#2, _Missing | "NA"], NumericQ],
BarChart[#2, PlotLabel -> #1, PlotTheme -> "Detailed"],
Nothing
] &,
Normal@Transpose@dsBenchmarks
]

Breakdown statistics
Partition benchmark results per system (or other criteria):
aRes = GroupBy[Normal@dsBenchmarks, #System &, Dataset];
aRes = Map[#[All, Select[#, NumericQ] &] &, aRes];
Separate the overall benchmark results from the benchmark component results:
aRes2 = Map[#[All, KeyTake[#, {"BenchmarkResult", "TotalTime"}] &] &, aRes];
aRes3 = Map[#[All, KeyDrop[#, {"BenchmarkResult", "TotalTime"}] &] &, aRes];
Show the overall benchmark results:
aRes2

Show distribution statistical plots per system:
aResPlots3 =
BoxWhiskerChart[Transpose[Normal[#[Values]]],
PlotLabel -> Row[{"Number of benchmarks:", Spacer[2], Length[#]}],
ChartStyle -> 56, ImageSize -> Medium, PlotTheme -> "Detailed",
ChartLegends -> Keys[Normal@#[[1]]]] & /@ aRes3;
Grid[List @@@ Normal[aResPlots3], Dividers -> All, FrameStyle -> GrayLevel[0.7]]

(Note, that we have to keep an eye on the number of available benchmarks per system. Those numbers are too small here...)
Older plots

Benchmark[]
not just screenshots. $\endgroup$Benchmark[]
.) $\endgroup$