Based on cleaningtheglass.com Rondo is a really bad player. First of all, he's almost 36 years old. The Cavs will be his 9th team in the last seven years. Nobody who's had him since the '14-'15 season wanted to keep him.
Compared to Rubio he's almost five years older and four inches shorter.
In terms of points per shot attempt, Rondo is in the 5th percentile; Rubio is in the 32nd. In assists per usage rate, Rondo is in the 100th percentile compared to the 83rd for Rubio. One thing about Rondo - he can dish them out.
In turnover percentage Rondo is in the 0th percentile, meaning he's in the worst 1% of point guards in that category. Rubio wasn't great, either, but at least he was in the 24th percentile. This isn't a recent development. In the last seven years Rondo has never been above the 16th percentile in turnover percentage and he's been well below that number most years.
You'd think after all those years in the NBA Rondo would be better at protecting the ball, but he's the worst in the league. At the same time, he dishes out more assists per minute than anybody.Apparently he throws a lot of high risk passes that either turn out to be turnovers or assists.
In terms of on/off numbers, Rondo is awful. The Lakers were 16.9 points per 100 possessions WORSE when he was on the floor. With Rubio in the game the Cavs were 4.9 points better.
Rondo talked about being excited to play with three seven-footers, having never done that before. Maybe throwing the ball to bigger targets will reduce his turnover rate. But if he's going to help this team and replace Rubio he needs to cut way back on the turnovers while keeping his assist rate up.