Finally platinumed it, fortunately most of the trophies have been designed so a grind is not necessary. The only ones i had to repeat missions for were El Train, where i had to restart the last one on the 3rd island twice on my second playthrough in order to hit the 25 kills target, and evil to the core, where i had to repeat the invisible conduit killing in the park a few times as they netted loads of XP in a short amount of time (far quicker than doing all of the optional missions i had missed).
My only annoyance (there were a few niggles, don't get me wrong, but the only thing that really cheesed me off i mean) was the shard collecting. But then, that was mostly my own fault. I had one shard i needed to collect just as i was scouring the coast of the second island so i decided getting a map online would be a good idea. I completely cleared all of the islands using the map yet still was missing one shard, i looked online again and saw they had revised the map, putting an extra shard in on the coast of the second island. I wouldn't mind too much but i was basically standing right next to the pier where this final shard was hidden when i decided to print off the maps. If i had been patient i would have saved two days of my life.
Overall, 9/10 from me. Excellent gameplay mechanics, brilliant story, some really varied and epic weapons, very varied missions (only one or two of the optional missions were rehashes of previous ones, every storyline mission was completely different; the development of GTAIV could have learned something from this) and surprisingly developed and interesting characters. My only complaint is that the good and evil choices were so clean cut and you HAD to follow one path or the other. I would have liked to be able to take a middle ground, for example the good and evil choice involving Trish near the end was nowhere near as clean cut as they made it out to be. I couldn't really decide which was the good option and which was the evil.