Monster Sigma Mythology - Need Answers

Back in the mid 1990s I fell into spools of Monster M Series M1500 and M2.4 Biwire. The M2.4 does not have the network terminator and I had to terminate the M1500 (don't do this as it takes forever, and ever, and ever). Before I knew it I had an entire system cabled with the much maligned Monster products and there they've stayed all these years, but now I have a 1 meter pair of the mythological M2000 Sigma interconnect in route.

I write this due to the complete lack of information on the net about upper end Monster cables. The new retro cables actually have some discussion on the net, but then you'll see claims that the old M2000 Sigma was better. Similar controversy may exist with the speaker cables with the old M2 Sigma.

The M2000 Sigma interconnect I purchased in ignorance thinking it was using the newer generation, low capacitance PEX dielectric first found in M1000i and the M2.4s biwire Speaker cables (cables are nearly black whereas older Monster M Series is gray.) I’ll update the table below with its capacitance which is likely frighteningly high. In searching I saw an Ad for M1500i, but without visual confirmation I belief this is a myth. (Or does M1500i exist?)

I am hoping the Agon community will help fill out this thread with details on the various monster top offerings. I'd like to keep this to M1000 and above interconnects and M2.2s Speaker cable and above. So some tabular info follows including capacitance which is a big issue for tube equipment (we can update values if anyone can provide missing numbers by measuring with capacitance meter)....

Interconnect (1 meter pair):
MODEL VERSION YEAR PRICE CAPACI NOTES
M1000 Laboratory Ref
M1000 Sonic Ref. Std.
M1000 Mk. II Sonic Ref.
M1000 Mk. III Sonic Ref. $200 162pf Isotec
M1000i PEX
M1000i Ultimate (PEX) PEX
M1500 $400 278pf
M1500i
M2000 Sigma $800

Speaker Cable (8 foot pair)
MODEL VERSION YEAR PRICE NOTES
M2 Sigma $2000
M2.4s Biwire $800 Best?
M2.2s

Decided to leave out Retro in table. Please discuss your sound experience with these. Monster has a bad name with audiophiles, but these cables were designed with technology licensed from Bruce Brisson of MIT fame. The earlier interconnects are extremely capacitive and that would account for their dark sound with some tube equipment. You do not want excess length! All of these are well liked to my knowledge except perhaps the M1000i ultimate which an Amazon reviewer said sounded more rolled off then his old M1000. M1500 considered sizeable step up from M1000. M2000 is not as big a step up. Until the Retro Gold, I don't think Monster put out anything above M1000i with the lower capacitance PEX dielectric.

On the speaker cable front I left out the older Monster stuff except the outrageously priced Sigma M2. The M2.4s is really, really good even at retail and can be had used easily enough given the Monster reputation among audiophiles (most of whom would be embarrassed to have it in their system). Don't be shy Monster lovers!