No difference if you run the full trial version ie with the trial registration code keyed in.
The colours can be just as punchy if not more if you choose the appropriate colour modes.
I like Silkypix so much that I am now using it almost full time.
In the full trial version, when you select the Colour menu on the top left, more colour options are made available eg. sRGB/Adobe RGB, and Colour modes like Memory Colours, Portrait 1 & 2, etc. Some of these are more punchy than Oly colours, maybe even too punchy but at least one of them would be suitable for any particular photo. This is not available in the free trial version.
Also, the built-in Silkypix colour profiles for Olympus DSLRs is quite good most of the time (but not all of the time). So you should check out the built-in Oly profile to see if the colours obtained are better than as the As Shot colours.