I've owned both. The Placette adds an extra silkiness to the highs, along with a an extended decay, and bit better air. But because I could only use single-ended connections, there was a definite weighting toward the highs leaving the bass regions sounding a bit enemic, IMO, and hence the appearance of an unbalanced presentation.
I should quality the above by stating I'm really committed to using XLR connections because of what those 2 additional volts do with my particular amp regarding bass and dynamics.
The X2.5 gives me dead quiet XLR connections (not all do this) and very good, pristine highs. But not quite to the extent of the Placette.
Further tweaking, connecting the ground to the X2.5 only (all other components are ungrounded), installing AudioPoints under my components, rack, and speakers all more than made up for the difference including adding in a bit silkiness the Placette offered.
But I also have to wonder what the Placette would have sounded like if I performed those tweaks while I still had it.
In the end, as with everything, it comes down to listener preferences. But both preamps are very good to excellent for the price.
-IMO