There are a lot of speakers that are a lot better than the Klipsch Quintet. But I am guessing that you might have been drawn to them, at least in part, because of their looks and small size?
You've mentioned an $800 budget. I'm guessing you would like a complete 5.1 speaker package for that price?
Your receiver was a great choice, by the way. The Pioneer VSX-1019 is one of the very best of the lower cost receivers out there right now, so congrats on that choice!
So let's get you some speakers and a sub that are worthy of that receiver choice, yes?
I'm going to start by making a suggestion that is a bit over your $800 budget. If you can see your way up to spending about $1100, the
SVSound S-Series Compact 5.1 Package is about as good as it gets for a complete 5.1 package. The system includes 4 of the SBS-01 small bookshelf speakers for Front L/R and surrounds; the SCS-01 Center; and the very capable PB10-NSD 10" subwoofer. The package itself is $950 and you'd be looking at roughly $150 for shipping.
The SVSound S-Series are very neutral and accurate speakers. They are a sealed design and they are not too picky about placement. You can mount them on the wall without too much negative effect on their sound. And if you can place them optimally, they will reward you with very clear and accurate sound. The PB10-NSD is a great performer and will have plenty of output for your room size. It is likely physically larger than you might expect, but that allows it to perform to a MUCH higher quality level than any sub that you will find in a store-bought package system.
If you want to stick to that $800 budget and you don't mind speakers that are physically a bit bigger and aesthetically a bit uglier
The
Behringer B2030P are basically unequalled when it comes to accuracy and sound quality for the price. You can find them online for even less than the Amazon price that I've linked. But five or six of them will set you back less than $400! You could mate those with the SVSound PB10-NSD or you could go for one of the even less expensive, but still very impressive subs from Elemental Designs (eD), like the
A2-300
That Behringer + eD combo would sound amazing, but it's kinda big and ugly
If you just want to keep things simple, keep things inexpensive and keep things pretty good looking, then we come to tSc
I'm quite fond of
this T-Series package. For the price, the sound quality is kind of unbelievable - except I've heard the Behringer B2030P, so my expectations for low-priced speakers are pretty darn high these days

The dipole surround speakers in this tSc package are a real treat. If movies and TV are your main sources, I personally prefer dipole surrounds as they create a more diffuse, ambient, "wrap-around" surround effect that more closely mimics a full-sized movie theater and prevents the surround speakers from being distracting.
If you want to go even more stylish and sleek-looking, then tSc has you covered there as well with one of their TSAT systems. I would recommend
this one for your room size and budget.
So those are four possibilities. I think you will find something to your liking among them

I certainly wouldn't get the Klipsch Quintet myself. Not with these options available
Best of luck!