To make your decision easy, please note the below
I own a Ritz Ldi which is one year old and done 13000km so far
1st free service 1000km : Rs.680/-
2nd free service 5000km : Rs.33/-
3rd free service 10000km : Rs.1900/-
Oil used us a regular mineral oil and there is absolutely no need to use synthetic oils
My next service is at 20000km and however i will just go for a simple service with a wash and wheel alignment,balancing at 15000km
Apart from above, I did not a spent a single rupee.
I was also thinking a lot before shifting to diesel especially on maintenance and it is very less than maintenance of petrol bike Suzuki Slingshot !! ( it costs me more with this as it gives 50kmpl and petrol is Rs.77/- per liter these days)
My Ritz Ldi gives me very precisely 19-20kmpl with AC in city and 22-23kmpl on highway with AC.
Now decide what to do