Advice on picking the best opportunities in AM - Internships (UK)

As the Question / Title says, AM and essentially how to begin your career (IN THE UK) - Couldn't find a related thread on here.

[a bit about me: 2nd Year UK target, 3 spring weeks in Professional Services (Pending), AM (non-convertible) and a Tech Firm (converted). Gunning for SA AM internships this year]

With SA offers arguably being the most important stage of initial recruitment, ensuring you make the right choice is imperative. For IB for example, you would consider and compare institution specific groups or desks if you had multiple offers. Assuming you land multiple Asset Management SA offers , what are points that you have to consider - to ensure you get off to the best possible start upon converting to a grad role

EG AUM (historic and forecast) vs Brand Name vs Client Structure vs Asset Classes vs Investment Strategy etc

Assuming one leaves after 2-3 years (after getting all 3 levels of CFA or whatever) ;

Would an unknown but growing Active Equity AM firm (say 6.5% AUM Year on Year increases) with £20bn AUM be a better pick at the summer internship level than a well known but shrinking Fixed Income focused institution with say £100+bn AUM?

What would be the best way to compare firms and the opportunities?