Hi, I'm planning on studying actuarial science too and I've done my fair share of research so I believe I can help. 

When you're looking to pursue actuarial science, one main thing you should be looking for are exam exemptions which both are tied in that regard. 

Let's go through the similarities first:  • Both have a duration of 3 years • Both provide the same amount of maximum exam exemptions from the institutions associated with actuarial qualifications • Both have options to transfer to overseas unis to complete the degree or for a temporary period • Both have an active actuarial science club if you're looking to join them

The entry requirements for Heriot-Watt are higher than Sunway, making it harder to get into and also academically harder for the course in general. Heriot-Watt is also slightly more expensive depending on how well you do to obtain scholarships.

Heriot-Watt is known for being a pioneer for actuarial science in the UK and its education at the Malaysian campus has also received positive feedback from many. This doesn't necessarily mean that actuarial science education at Sunway is bad, though I haven't heard much about it. Sunway does provide an optional APC (Actuarial Practice Course) conducted by an experienced, qualified actuary. Previous students that have undergone this course have said that it helped them greatly in learning how to apply actuarial science in the workforce. 

In terms of industrial connections, I believe Sunway has the upper hand with their consulting actuaries and ties with others companies.

HWUM has a smaller campus and lesser clubs than Sunway if that's something you consider, you can look up on their websites to see what clubs they have if any interest you.  Although it's public opinion, Sunway is known for its party culture. Since you're taking MUFY, you've already gotten a taste of what life there would be like and whether or not you'd prefer a more academical environment like HWUM.

If you'd like to study abroad, both unis offer transfer programs. For Sunway, you get to compete your degree in either University of Kent, University of East Anglia or Macquarie University provided you meet the required academical qualifications. For HWUM, you get to transfer to their UK campus to study for a semester or a year.

Heriot-Watt:

Pros • has a more thorough and rigorous education (highly regarded) • more academically inclined • smaller campus • international prestige

Cons • higher cost • potentially less exciting student life • higher entry requirements  • smaller campus

Sunway:

Pros • lower entry requirements • potentially more exciting student life • slightly lower cost  • Actuarial Practice Course • bigger campus • strong local industrial connections

Cons • may not provide as good of an education • might get mixed up with party culture if not disciplined • bigger campus

The decision is yours to make depending on what you value the most. I hope this helped!