Lonnie - More teeth is a biggie, but there are several other parameters involved in addition to more teeth, and it starts getting a lot more confusing from there. Precision, sharpness, and tooth geometry have quite an impact too.
More hook tends to mean a slightly lower feed resistance but with slightly more tearout, but ease of feeding/resistance is also dependent on the tooth grind, mass of the blades, etc. Tearout is also dependent on tooth grind, feedrate, blade height, material, etc.
Precision is much harder to determine, but I'd assume that more expensive sets made in the US, Germany, Italy, Israel, Japan, etc., will tend to have better precision than a cheap set made in China. My $200 Infinity is made in Italy and has fewer teeth than my $300 American made Systimatic, yet the Infinity is a little cleaner cutting with less tearout, so I assume it's performance advantage is due to tooth configuration and precision, though both are excellent. A $150 to $300 set will tend to have a better cut than a $40 set, but you don't necessarily need to spend $200 to get an acceptable cut. You can get what you pay for if you're careful.
The H7777 is a copy of the Systimatic 42SFine design, which was excellent but was a $300 set made with high precision in the USA, the Grizzly set is made in China with a softer less desirable grade of carbide, and likely less precision. It might still perform well for you, but I haven't used it so I can't say from personal experience. You'll see even cheaper sets from Harbor Freight. Oshlun offers a set of the same design that uses a harder grade of carbide for ~ $80 (Holbren.com has it). But if $80+ is going to be spent, I'd rather spend $104 on the 7670 set and know what I'm getting. BTW, the DW set is closer in design to the Forrest Dado King.
Systimatic S42Fine dado / (also see pic of Oshlun & Grizzly dado 8"):