...0.3 mg [buprenorphine] being approximately equivalent to 10 mg morphine sulfate in analgesic and respiratory depressant effects in adults
Presumably, 0.3 mg buprenorphine is equivalent to 10 mg MS in recreational value as well.
Overall though, I don't think it seems like the greatest opiate out there...it's definitely not one of the most euphoric opiates available.