I watched PS2 in theatres. It convincingly ties up the story that began in PS1, though differently from the plot of the novel. A good artist also knows the deficiencies of his medium. So Mani Rathnam, who is aware of the mammoth that he has decided to adapt on screen, chose to trim the complex novel and make a straightforward movie. Under the time and budgetary restrictions, this seems to be the best version that could be made. He also chose to add some action and war scenes to appeal to the viewers' appetite for spectacles, all the while respecting logic and gravity. He has also cut short the importance of several characters who are shown in the first part. The movie is very quick in its pacing, though it takes time to breathe during some dramatic scenes.
Aishwarya Rai and Vikram steal the show with some great emotional scenes. All other characters, including Ponniyin Selvan, get one or two scenes to shine, except those few whose roles were totally butchered. But my only sympathy is with Sarath Kumar's character, who has a great arc in the novel that unfortunately wasn't realised in the movie. Each actor, irrespective of screen time, has done a good job, even if it is just showing up and looking good.
The songs in PS2 are not that catchy. After watching PS1, the tunes of Ponni Nadi and Devaralan Attam refused to get out of my head for days. But PS2 lacked in that department. All the songs complement the scenes but don't stand out. Background music heavily uses operatic sounds along with traditional Indian classical and folk tunes. The use of opera imparts a grandiose effect to the high-voltage confrontation scenes.
If you want a good entertainer that is aesthetically pleasing and not over the top, PS2 is satisfactory. If you have an obsession with the book adaptation being done line by line for the movie, it's better to skip it. If made into a series, this could give GOT serious competition with all the intricacies, subplots, and conspiracies, though that is not to be. Mani Rathnam, to his credit, manages not to spoil the legacy of the Cholas, Kalki, and the epic novel Ponniyin Selvan.