I have an earlier Presonius channelstrip model, the VXP. It sounds great but I can't say it gives me a "warmer sound" than I get by plugging the PASV4 directly into my RME Fireface400 audio interface, at instrument level (laptop rig stereo to PA stagebox). I have grown a huge fan to the PASV4 pickup and think it sounds excellent just as it is, line in with only a little treble cut off and subtle compressing.
The "tube saturation" of the channel strip is something I never use because I don't like its sound, but maybe the algorithm has been improved in the model you are looking at? I sometimes use the Prosonic for studio recordings of sax because it has a great expander that is capable of masking out some metallic action noise you get from the mechanics of a tenor sax. But I have almost stopped using the channelstrip's dynamic EQ. With the RME and 24 bit recording it is faster, equally good sounding and a lot safer to do the processing post recording. I used the Presonus quite successfully live, on a tour eight years ago but then to achieve a more articulated tenor sax PA sound from a clip-on fly mic (using the awesome AKG C 414 B-TL2 in the studio and it is just like the PASV4: "plug-n-play")
You could say that my sonic ideals for Stick playing draws more on the John Abercrombie jazz guitar sound than on the Chris Squire Rickenbacker bass sound
)