I have used aliexpress for purchases (not to india) but to the UK. Delivery is slow especially if you take the free option.
Quality is down to the sellers there, I have had some very nice products and some terrible. Aliexpress do provide a conflict mediation service (a bit like ebay) and I found they favored myself when I was complaining on quality issues.
Custom charges not sure what import limit you have in India but anything I have purchased has came in with a $10 value marked on it even if it was more than that.
Prices on the site vary dramatically, if there is something you wish to get and are not in a rush for its sometimes worth waiting a month as there are regular 5-30% discounts offered and if one of them occurs on something on your wish list aliexpress will email you.
(I have no affiliation with aliexpress other than being a customer).