companies that modify equipment...opinions

hi everyone, im wondering if anyone has opinions on these companies that do mods. this question popped in my head as i have been reading up on modwright sony 5400s/oppos.

i also see that vse (vacuum state electronics in switzerland for example) also does mods on the sony 5400 etc. i also came across some other companies(forgot names) that heavily mod cd players in the united states.

im wondering if anyone knows or has heard and compared performance from the same piece (front ends in particular) but modded by different companies... for example modwright tube mods vs vacuum state electronics level 7 mod on a sony 5400 etc.
what are your preferences and thoughts.

thanks