I haven`t tried it (I am not allowed to take Tadafil or Sildenafil products for medical reasons) but from the purely medical point of view it depends on whether you mean tablets containing 200mg of Sildenafil Citrate or those containing 100mg Sildenafil Citrate + 100 mg Dapoxetine (which is normally prescribed to treat premature ejaculation).
200mg of Kamagra (Sildenafil Citrate) will not result in any increased size or strength of erection, but merely make it last a bit longer. However it also multiplies considerably the risk of serious effects and should not be even considered without first having a full medical check.
Kamagra 200 on the other hand is merely the standard Kamagra of 100mg Sildenafil plus 100gm Dapoxetine; again it will not produce any greater or stronger erection but it will simply delay your ejaculation. Again, the combination of the 2 drugs increases the risk of side effects and more serious effects than with pure Kamagra
"Containing a large 200mg of Sildenafil Citrate, Viagra 200 is one of the largest dosages of generic Viagra on the market today.
Designed for use by patients with a history of using ED medication, the 200mg Generic Viagra Tablet has been reported to last up to 6 hours. It has also been reported to produce a more successful reaction in patients who may have seen results drop with a smaller dosage.
Before taking this 200mg dosage of Generic Viagra, it is important to discuss this carefully with a doctor and seek assurances that such a large dosage is safe for you to take.
This product is sold in packs of 10 tablets."
I've had Cialis 20 mg pills on prescription from my GP which worked OK when I had a regular fuck buddy because they lasted for a couple of days. GP was fine with that - I don't have any medical problems apart from ED. I just need to get it up for the duration of a one hour punt.