Denon cartridge vs Audio Technica cartridge

I haven't heard the Denon, but I did own an AT150MLX and it's excellent. A very good tracker and a very precise and accurate sound. Punchy bass and clear, pure highs. Could be a little bright at times, but system dependent. Overall great dynamics. Would not hesitate to purchase again.

Without knowing the effective mass of the tonearm, my guess is the DL-301 and AT150MLX would be a better match. The DL-103 needs a heavy arm -- ideally 14-15 grams. I doubt your Denon arm is that heavy.