I have a 12" Dewalt slider.. GREAT saw, but I don't know that I need it, or want it...
It has come in handy, for A LOT of stuff, but as JimD said.. deflection, heavy...etc. I have set it up to be pretty accurate, but when it is all said and done, it will not be a perfect "90" degree, 45", etc., cut. Deflection and they are not meant to be 100%.. heck, even 99% (?) accurate. But for what you are looking to do.. I am sure it will be perfect.
When I was contemplating selling my slider, I was looking at the 7-1/4", 10, non sliding 12".. and from a lot of reviews, I decided against the 7-1/4". One of the reasons was the internals, "flimsiness" build quality, when it came to the 10"+
If I needed something for trim work, I would go 10" non sliding, but with a minimum of single bevel. Not sure how wide of trim you need to cut, but I would look at the max cut of the 10".. 90 degree and 45, and see if that would work for you.
Hope my opinions\thoughts help.