I will recommend the GR07 because it offers fairly wide soundstage, crisp clear mids, highs and tigh punchy bass but overall balanced and fun sounding IEMs. The B2 will offers better details in highs with less punchy bass than GR07, so if you want highly detailed IEMs then B2 willbe better pick and if need overall detailed, balanced yet fun sounding IEMs then GR07 are great buy.