DSP will have higher accuracy in balance but musicality is always with the 300BI really enjoyed the Kii room in the Mumbai audio show (my top 3 rooms in that brief sojourn).
As @bhagwan said, I found 15L quite steep for what they offered.
Meanwhile on @vnavin thoughts of DSP vs non-DSP I have just ordered the Lyngdorf 3400 (DAC+preamp+amp+room correction+music server in one box) and in September, will be comparing it to my 300b tube SET monoblocks with tube DAC to see what works better with my speakers and room. Should be interesting. This for me will be the ultimate test between DSP vs purist approach to audio.
Will report back.