There are many reputable companies like Supmeds, Ukmedix and many other.There is not so many difference between Viagra, Kamagra and many other brands of Sildenafil. It might be a difference in color
Not great advice, some of these generics are made on dirty floors in China/Vietnam would you eat dinner where they place raw chicken on the floor don't risk your health with generics.
Sildenafil is an active ingredient. Viagra is a brand name. Generic name is sildenafil. It is absolutely the same thing. But anyway you must try to see what it does. It is better to order small pack if you afraid to be poisoned )))
I order at Supmeds (the cheapest viagra on the net- someth like 0.7$/pill).