I'm Rajiv, and I run InstagramFetch, so take this with that in mind. I'll tell you what I know about our tool for sure and keep the SnapInsta side to what's publicly visible.
Both are browser-based downloaders. You paste a public Instagram link and get a file back. For most people, either will do the job on a single Reel.
They differ in ads, number of steps, which formats they offer, and how they handle links that fail. Limits change often, so check SnapInsta's site for its current details.
Comparison
Criteria
InstagramFetch
SnapInsta
Works in browser
Yes
Yes
Instagram login required
No
Generally no, check their site
Public posts only
Yes
Check their site
Reels / videos
Yes
Yes
Photos and carousels
Yes
Check their site
Stories
Yes (public)
Check their site
Audio / MP3
Yes
Check their site
Profile pictures
Yes
Check their site
Watermark added
No
Check their site
Upscaling
No, original quality only
Check their site
Price
Free
Check their site
When to pick InstagramFetch
You want one place for Reels, carousels, Stories, MP3 and profile pictures, with separate step-by-step guides for each device.
When SnapInsta might suit you
You already use it and it works for your links. You don't need to switch.