Drive them both. I think at 100mph+, the 1 series feels much more unstable and scary on not so perfect roads. My impression shared by some others who have driven/owned both. I also think its less aerodynamic and has a more restrictive base exhaust. Also if you were to weight reduce a E90 to the weight of the 135i, the E90 is faster with both on stock rear catbacks.
2011 Alpine 335d M-Sport 12.34 @ 110.48mph
2015 i3 Terra
2008 Black 335i Sedan. 11.11@ 129.47 mph
2008 Monaco Blue JB3 2.0 335i Coupe. 11.33 @ 132.77 mph (N54 stock turbo trap speed WR)
60-130mph: 6.95 seconds stock turbo WR (.16% slope)