I've had varying experiences with both bands live.
Porcupine Tree in 1995 was amazing, still one of my favourite gigs ever. Subsequent shows in 2000 and 2007 were pretty dull, I left both early.
SW is diminishing returns as well: gigs with his early band line-ups were great - Adam Holzman, Theo Travis, Guthrie Govan, Nick Beggs, Marco Minneman. Then the material started losing interest for me, shows and albums from Hand Cannot Erase onwards weren't as engaging.