I am a current 3rd year student at Aberystwyth and I am really enjoying it here!
Aberystwyth is a great place to be a student, there is a great feel to the town and there is always plenty to do and see. The University has a very friendly and welcoming feel and has even been named Welsh University of the Year for 2020 in The Sunday Times Good University Guide.
Looking at the modules offered at each university is a really good way of comparing the courses to see which may interest you more. This is something I did when comparing universities when I applied and helped me make my decision. It may also be worth looking at how each course is assessed, to compare which style of assessment may suit the way you work best. Rankings are useful to look at, but it is also important to think about how the course is suited to your interests and future career goals and the skills you will get from the course.
Also looking to see if the courses are accredited may also be useful in comparing courses, here at Aberystwyth the Computer Science course is accredited by the Chartered Institute for IT (BCS) on behalf of the Engineering Council.
I would also recommend speaking to currents students about their experience at each university as well as current academic staff. This may help give you more of a feel of each university and help in your decision making.
On the UCAS website you can chat to students from different universities studying different courses through Unibuddy. Several other students and I from Aberystwyth are available to chat, look here if interested!
Please let me know if you have any other questions, happy to help!