For me, simple transitions in LSP 2.5 are running great. I have a few issues with lights lagging when I use the more complex Macros (like color wipes)
But apart from that LSP is working just fine for me.
I do see an option for XLights to convert to Conductor format, so I assume it maybe able to convert from LSP 2.5 format directly to the conductor format (although I haven't tried it)
I do know that LSP 2.5 has a menu item to export LSP 2.5 files directly to Conductor format, but that is broken right now.
You can export from LSP 2.5 to LOR file format, and then run that file though FrankR's tool and get it to load into xLights scheduler relatively easily