I had read the occasional post saying that the 50 letter piece collectable was worth hunting for. So while it was pretty annoying in having to head over to the living room to read up on the collectibles list on Rockstar's social club, and then head back to my room to then locate it over and over, I thought it would all be worth it and would lead to something nifty.
But of course... nothing of any note really happens. I mean OK, you solve the murder and uncover the killer, but the killer is nobody of any real interest or importance, and I was hoping it would be a more spookier sort of encounter... I got into the mood and everything once the Stranger mission popped up on the map; I made sure to go at night, and I was sneaking into the guy's house expecting some sort of ambush. Instead you meet the guy, chase him down (or not, I guess), kill him and... well, that's that then.
I've still just left there for now, so maybe there's at least an unlockable car or outfit?... Even still, I was really banking on Rockstar using this collectible set to give you a horror themed mission at the end of it all; like, you're visited by Leonora's ghost, or you encounter Dreyfuss on his movie set and you have to try and figure out what's real and what's an illusion or something. They should have at least made the killer to be someone recognisable, and considering that it's a guy tied to the movie industry and Solomon Richards, wouldn't it have made more sense for this to be a mission for Michael instead of Franklin?...
Honestly besides going for the 100% completionist route, it frankly didn't feel like it was worth the effort.
EDIT: Oh, but it at least helped introduce me to some crazy hitchhiker lady who Trevor can apparently have booty calls with whilst I was searching for the letter pieces. So, what are the other collectible 'rewards' like? The Epsilon stuff and the alien parts I mean.