The "better" part of the search relates to data compression. The versions that grow to ~172 MB in cache are the ones that have intelligently saved thumbnails and page fragments. In real terms:

This version is widely considered "better" for specific use cases where storage space and RAM efficiency are the primary concerns. Why UC Mini 1.72 MB is a Better Choice for Specific Users

Modern browsers often consume hundreds of megabytes of RAM. The 1.72 MB version is designed for devices with 512MB of RAM or less, ensuring the rest of your phone doesn't lag while you browse.

Why UC Mini is the Perfect Choice for Laptop Users - Ask.com

Suggested alternatives (lightweight browsers)

Have you tried this version of UC Mini? Let us know in the comments if it improved your browsing speed!