I think they aren't deserving of their at-large bid, but I do believe they can cause Marquette problems.
Iona didn't have any top 50 wins. If they had beat Purdue, they would of had more top 50 opportunities against Temple, Alabama, and/or Wichita State. If they had gotten past Purdue, I would consider them worthy of an at-large.
Overall, they are a very strong team with one of the best point guards in the country (Scott Machado). They also get great offensive production from Glover and Jones, and they are the #1 scoring team in the country.
Assuming they beat BYU in the first four, their game vs. Marquette should be fun to watch.