I'm possibly the other way around.
I much prefer portal 2 in the way it uses the new dynamics in the game, looks better IMO, and actually has an element of a story developing behind it. Portal 1 was fun as a standalone game, but I didn't personally feel that there was a larger world outside of it, and to me, lacked much of a backstory really. But it was very much a new idea having a puzzle based game rather than a fps style game, so I can imagine valves reluctance in putting too much effort into P1 compared to P2.
Whichever way - Portal is free (or has been free enough times for you to not need to buy it), so you have no excuse to not play through it