I am the first to admit that I am a Sprint fanboy. I have been with them for 8 years and I love the company. I have had as many as 30 lines with them, including tablets and MiFi hotspots and old Nextel phones. To control business expenses, I have frequently done price comparisons to Verizon, ATT, and T-Mobile. Sprint has ALWAYS come out as the best deal. (Although TMo with their new plans for bringing your own phone looks competitive.)
All this is why it pains me to say that I am considering a switch to ATT or TMo. The primary reason is in anticipation of Google's new Nexus plans (Fingers Crossed:
http://www.androidcentral.com/multiple-nexus-devices-could-change-android-forever), which is why I would not switch to Verizon. But the secondary reason is because of data speeds.
Coincidentally, I am also in Chino Hills (71/Pine). I tried to run some Speedtests for you but gave up soon because the network wouldn't even connect (bad sign). But here are some results from my SGS2 Epic 4GTouch on 3G:
Ping-1064 Down-.12mb Up-.11mb
Ping-803 Down-.11mb Up-.10mb
Ping-892 Down-.12mb Up-.13mb
Ping-164 Down-.16mb Up-.05mb
And here are some from my iPhone 4S:
Ping-1410 Down-.06mb Up-.00mb
Ping-859 Down-.01mb Up-.00mb
Ping-1040 Down-.06mb Up-.00mb
I am severely tempted by the EVO LTE and promises of LTE in the IE. Having been with Sprint since before data speeds were even a thing, I think I generally don't know what I am missing. But I see the speeds that others are getting on other networks and I know the frustration of no or slow data speeds on Sprint. I honestly think that the reason Phil is taking so long to publish his EVO LTE review is because he loves the phone and wants to recommend it but just cannot bring himself to recommend a phone on Sprint's network.
Data is almost the entirety of what I do with my phone. I don't do a lot of calling on it but rarely have dropped calls when I do. I don't SMS a lot because I do all of my texting through Google Voice which uses data. But I have rarely had trouble with SMS on Sprint's network.
Since Sprint recently ended their loyalty rewards program (I used to be able to upgrade every phone on my account every 12 months, now it is 22 months like all the other carriers), I have even less incentive to stay with them, except I really do like them as a company. In the end, I am pretty sure I will get the EVO LTE based on the awesomeness of that phone and the promise of future LTE. But in 6 months, if Google does announce their rumored Nexus plan, I will pay the ETF and switch my primary line to ATT or TMo but leave all my other lines with Sprint. I just don't want to be stuck in the Dark Ages of data speed any longer on the device I use the most.
So if call quality, SMS, and your budget are your top concerns, I could not recommend Sprint highly enough. They are wonderful. But if your top priority is data speed (as mine is increasingly becoming), it pains me to say that I would stay away from Sprint, unless you are very confident that LTE is coming to us in the IE. Best of luck!