I decided to switch to Apriso (similar to Lialda in that it's a once-daily mesalamine, but is formulated to start dissolving at a lower pH) because I was having trouble remembering to take my noon dose a lot, and sometimes my evening dose. One of the biggest reasons UCers flare is because of not taking medicine as prescribed because they forget doses. So my guess is your GI is suggesting it b/c of that.
Status: Remission since late May 2009!
Symptoms began in November 2008, ~4 weeks after giving birth to my son.
Diagnosed with pancolitis on 1/30/09
Currently taking Apriso (4 pills ONCE!! daily), Rowasa twice weekly, Natural Factors Ultimate probiotic 12/12 Formula, and Zoloft (25 mg).