Yea there are a few key differences:
1. The 202hd is an actual audio interface and connects to your computer via USB Bus and allows you to actually connect to your computer and record through it without buying tons of cable adapters that run into your computer like 1/4 inch to 3.5mm and in theory you could get the mini mixer board to work but its much less practical
2. The mixer board does not show the actual Bit rate, and frequency which is usually a bad ish sign. on the other hand the 202hd is 24 bit and 192 khz which is basically as high as you can go.
3. the main advantage of having the mixer is having an easy fast way to eq your voice the 202 doesnt have that but as long as you buy a decent mic and some basic filtering software or something you wont really need it.
so yea i use the 204hd which is the same thing with more outputs and a midi input not much better and the sound will be much cleaner compared to the mixer i get very little white noise especially if you use balanced cables. I run my 2 jbl 308 speakers off of them and it works great.
so id definitely say just buy the 204hd its what you want for what you want to use it for.
Cheers.