Assuming you are buying either both ( Base + Super top up) or high sum insured afresh.

Advantage of Base Policy + Super Top Up.

1. It may be economical.

Disadvantage of Base Policy + Super Top Up

1. The terms and conditions may not be equivalent for Base and Super top Up. For example there is mis-match between waiting periods. Hence, it's advisable to read the terms and conditions for both the policies before buying. It can happen in policies of same company also.
2. Condition under which claims will be paid under super top up policy may be different. For example, you have bought a policy of 5 lakh base and super top up of 10 lakh with a deductible of 5 from two different companies. You have claim of 6 lakhs and 5 lakhs has been paid by the base policy. The second company may or may not pay the remaining claim stating that 5 lakh was only payable. 1 lakh was the amount deducted for non payable and hence nothing will be paid.
3. You have to follow the process of claim settlement twice rather than once.

If you are buying a policy for first time, I would suggest to go for higher sum insured. If you already have a base policy then you may think of super top up.

Nilesh, appreciate putting this on the Forum., as this is always a query in every buyers mind, while making the discussion and decision.

Before putting forth response on query, it is always recommended having a single higher Sum Assured policy, as compared to Base + Super Top Up, if cash flow allows.

ALSO, while we are on this topic, one point to clarify (a myth to kick off)- One can even buy a Top-up without have any base individual or floater plan.

Now coming to you query (I understand here that both the policy are bought on same day and both started on the same day- Like policy start day is say 1-1-20 and both started together 5 years ago on same date)

ADVANTAGES - (Rather 2 advantages that I can think of)

_The premium cost could be cheaper or lower, then the same company.

_You become wiser by practical experience once you claim, especially multiple times.

DISADVANTAGES -

_ Double process of paper submission to 2 different cos.

_Time lapse is generally observed while there is switch from one co.to another, especially in case of cashless claim, while the treatment is going on in hospital.

_ Time lapse, even when reimbursement, both cos.check with the other, which again increases queries from the claims department and again claim payment delays.

_ There are higher chances of losses as if one declines some expenses, the other may as well.

_ There is a term used in mediclaim which is called "WITHIN A POLICY YEAR / TERM" which may differ between the 2 policy (base & super top-up) (It is also called within 2 policy anniversaries)

PS: Please beware- Mediclaim policy is a Health Insurance decision primarily and so Health cost cover, and related operational ease needs to be top priority, rather than monetary which can be 7th on the evaluation list to filter and decide on a Medical cost Risk Solution.

I always say, if and when hospitalization occurs, one only need to concentrate on best treatment from the best treatment provider. Under that condition, if you have to run around agent and / or insurance co.and hospital staff for operational things and if in case arranging cash for treatment, that's the worst condition which one has thought to avoid while buying insurance policy.