Actually have used all of them, played with them a lot, and did a lot of side by side comparisons. Here is my take:
The Samson definitely offers the best value as far as sound quality goes. It is also very small by comparison and simply just offers great sound quality for the price for a USB mic. The Snowball by comparison sounded 'cheaper', almost webcam like at times and really didn't sound any better than my Logitech C920 webcam! The Samson Meteor had a much fuller and richer sound, which actually very VERY close to how the Blue Yeti sounded. The Yeti gained the advantage over the Samson with the additional features it offered in different directional options via a selector knob in the back. The knobs on all the mics did feel cheap and plasticy, but they worked, though being on the mic did present the problem of being heard while adjusting.
Overall, if you want the best sound quality, the Yeti or Samson Meteor offered the best solution. The Meteor also had the advantage of being MUCH smaller than the Yeti, less than half it's size. The Yeti, by comparison, is HUGE. I seriously underestimated the size of the Yeti, and was one of the biggest turn-offs for me on it. It is big and heavy, while the Samson was the smallest, even a lot smaller than the Snowball. Between the Yeti and Meteor, I would pick the Meteor if I didn't care about the directional features on the Yeti. If that is a big deal for you, then the Yeti is worth it. Honestly skip the Snowball all-together.
The setup I run now though is a Monoprice 600800 mic, Rode mic arm, fed to a Behringer 802 mixer, which I have mix-minus fed into my onboard sound (ASUS Crosshair V Formula-Z). LOVE the setup more as it gives me more control over everything. If you plan on doing anything serious, using a mixer is going to be in your future. Overall, the setup cost about $250 excluding cables. I would start with the Samson though, and build up from there. For how cheap it is, you really can't go wrong, and even if you upgrade in the future, you will always find a good use for a small, cheap USB mic with great sound quality.
What does have a much larger effect on the sound quality will be things like positioning, shock mounts, pop filters, and such. Here is a sample of what my setup sounds like with the equalizer set neutral, and the only thing changing is the distance, and whether or not I use a pop filter.
Mic Test