HC-110 is amazing stuff, cheap, long lasting and darn it, the results are good! I got some HC-110 first and bought some Microphen and DD-X to try. At a convenient point a smaller bottle of the HC-110 filled to the top I started using DD-X and it is good but it doesn't seem to be that much better than HC-110, if better at all. I used some of each today, Delta 400 in DD-X 1+4 and T-Max 100 in HC-110 dilution B 1+31, both worked well.
HC-110 is always a bit yellow to me. The syrup is yellow to begin with. DD-X is clear by comparison until it starts to go bad.