We came to Costa Rica in 2009 and did the 2 day Pacuare trip staying at Pacuare lodge. This visit tried to rebook but they wouldn't pick us up from our accommodation ( even tho it was just off Highway 32 (!). so looked at alternatives and booked with Rios, which is much less expensive.
The differences - rafting great with both, but you get significantly more on day 1 with Rios as the put in is higher up. Our guide Albert was superb and knew the river well as he had been born at Rios Lodge!
Rooms are nicer at Pacuare Lodge but no electric or hot water. At Rios we had a standard room and also a Deluxe room. Standard a bit basic but fine for 1 night. Deluxe more spacious and smarter "feel2 and river view. Hot water showers& electric ( their own hydroelectric) in both.
Food better at Pacuare, but still fine at Rios. House fruit punch with local vodka went down well ( included).
At Rios did a hike to a waterfall and a 4 line zip wire all incuded in price. At Pacuare you pay for the extras.
We had a wonderful 2 days and if returning would book Rios again.