I have looked into going to Algonquin.  Even have a map.
If I remember correctly, it is more regulated than Q, more like BW.  You have to "post" a trip itinerary as to which lake you will camp on which night; and some of the lakes have limits as to how many nights you can stay - for some of the "entry" lakes the limit is only one night.  It is also not entirely a wilderness park like Q is.  Two thirds of the park is open to logging (and maybe mining?) - there are some sections designated as wilderness though.  The portages do average much longer than Q, and it is definitely more busy.  Much more river travel available than in Q.   I have seen it said somewherre that Q is the 2nd most popular PP, after Algonquin.  You  probably want to avoid the "highway 60 corridor", which has a lot of roadside access and car camping.
I think fishing is mainly for Brook and Lake Trout.  It might be worth a trip someday, but coming from the West, it is  a lot farther to drive than Q.