M,
At least in my case, the Dr. prescribed 5mg Cialis per day. My insurance only pays for 8 pills per month (regardless of strength) so I got the RX written for 20mg tablets. Bought a pill cutter at the pharmacy. Cut in quarters, that covers the month.
I don't use the Indian pharmacy companies (long story, not related to trust issues, just the customs complications), but I have tried the Tadalafil "Megalis" pills (Cialis equivalent) from ADC with similar results, slightly different side effects, but nothing to complain about.
Viagra is out for me due to the vision side effects.