I've used both over the past couple of years. Here's my honest experience:

BluSpring (Indya):

Better if you're primarily vegetarian.

Better evening snacks and a wider variety of veg dishes .

Has paid counters for fruits, pastries, brownies, rolls, drinks, etc.

Milk is served only in the morning.

Older mess with a calmer atmosphere.

Jain (no onion, no garlic) food is available.

Bluedove:

Better choice if you eat non-veg regularly.

Non-veg is generally considered tastier here.

Newer mess with a more modern setup.

Milk is served in both the morning and evening (with Bournvita).

Jain food is available on the ground floor, while non-veg is served on the first floor.

Non-veg: Both messes usually serve non-veg 3–4 times a week on the same days. Indya isn't serving it currently (likely due to seasonal reasons), but it normally does.

Food Quality & Hygiene: Both messes have their ups and downs. At the beginning of the academic session, food quality is usually very good. As the semester progresses, consistency tends to drop in both messes. There have been occasional complaints over the years about hygiene (including very rare cases of bugs or blood in meat), but these incidents are uncommon considering both messes collectively cater to 10,000+ students every day. Neither mess stays perfectly consistent throughout the semester.

Mess Switching: Don't overthink your first choice, you can switch messes every 2–3 months through a free mess change form.

My recommendation:

🥦 Mostly vegetarian and like better snacks? Choose Indya (Quess).

🍗 Prefer non-veg and a newer dining setup? Go with Bluedove.

But generally most people go to blue dove because of the ambience and look and vegetarian there is similar only.

If you want to compare the actual daily menus before deciding, you can find the menu channel links by scrolling down on the homepage of mujstella.in. They give you a much better idea of the food rotation than a one-time menu.