Hello Ankur!
Jesse from the Guru Team here.
The two apps that you mentioned are pretty unique in terms of the functionality that they offer. There arent really any alternatives that are going to meet your requirements across the board.
"Save Measurement feature kind of thing (Just like billing address) so that when he re-orders again, he can select the previous measurements and change if required"
I suspect this will be difficult to achieve as that information will need to be stored somewhere and associated with a customer account somehow, but I am always surprised what is possible through custom development and working with the API.
If this is vital to your business model and you have the budget for custom development I would recommend working with a Shopify Expert to explore having something like this tailored to your specific needs.
http://experts.shopify.com/developers
The helping guide would be easy enough to add to the product descripton itself, as you can embed photos or videos there.
Feel free to reach out at any time if you have any other questions.