Pros: Above average bass, Not bad treble, Horizontal soundstage with full depth (lots of mid layers)
coming from vsd3/s, i felt the same vsonic signature, not too far. it's soundstage offered slightly more depth to me somehow. vsd3/s are have big sounding mids which makes the soundstage more vertical, they certainly do not totally lack depth like the ostry kc06a but "feel" slightly more vertical. it's just a feel, not a day/night difference and nothing that will affect to a buying choice. i mean they're still superior.
at first gr02 really impressed me because i was expecting something much bad considering the $25 price paid (like xiaomi piston, oh i want to puke when i remember that item). but yes there's some differences which might affect to a buying choice if we compare against vsd3/s, especially with the $35 ordinary price tag. just for $5-10 more you're gonna get bigger mids with more bass acoustic & treble seperation. gr02 is rather a sneak peak to the vsonic products and for the discounted price, it's ok i think. if you're low on money i think you can live with it (i'm only saying this for the discounted $25 price).
i don't know how it'll stand against koss budget products however. i think koss can do some damage on this. koss products have more bass for shure. their mids are bigger than gr/r02 but vsonic still leads on mid layer seperation and their highs are more bright. i'll make my conclusion about koss vs vsonic when i get some ruk30/plug into my body again (i'll get a ruk30 again soon). same goes for the brainwavz r1, it's also something comparable to vsonic (with the discounted $20-$35 price especially) but i liked koss/vsonic more to r1, due to ease of driving & stable frequency balance, add build quality to that. r1 also has bigger mids & bass acoustic if i'm remembering right (my 2nd unit of r1 is also coming soon).
g/r02's bass frequencies coming very flat, you need more amplification on 30hz deep bass (strong bass frequencies like 125hz also comes unamped but not as much as deep bass) than most of bassy models out there. be sure to feed it right to get more bass.