Actually at a dilution of 1+29 and assuming you use the likes of DDX which many do and at the recommended 1+4 dilution then the dedicated developer works out cheaper. It is worth looking at Digital Truth's website as there is a test of Silvermax in the dedicated dev and in Rodinal and a comparison with Fomapan
Unfortunately it was compared to say Ilford D100, TMax 100, Acros or even FP4+.
There didn't see to be a lot in it and Silvermax didn't look noticeably better in the dedicated dev than in Rodinal but others' opinions may differ
"Starting values for different developers at 20°C:
Silvermax dev. 1+29 11 Min.
ADONAL/Rodinal 1+25: 8 Min.
ADONAL/Rodinal 1+50: 12 Min.
ATOMAL: 8-10 Min.
D 76/ID 11: 9 Min.
HC-110: 7 Min.
FX-39: 8 Min.
XTOL: 7 Min.
Agitating:
The first 30 seconds constantly and after this 4 times per minute.
If your prefered developer is not listed try the value for APX 100 and deduct the time by 10%"