I don't think you'll be unhappy with either receiver. The Pioneer will be a bit more powerful for stereo listening, not sure for surround sound (the higher rating doesn't necessarily mean more power when all channels are driven). I also think for an entry level receiver, the Pioneer will be a bit better because it will be a bit more forgiving on music whereas the faults in the entry Onkyo may be more obvious (onkyo may be more detailed but in an entry level receiver, this may not be a good thing).
With your speakers, you can't go wrong. I personally would buy whichever fit best/you liked the look of.