I'm in the rare position where I actually own both a 335i (E90) and 135i, so hopefully I can offer a different perspective. First and most of all, the choice is largely dependent upon what the OP is looking for.
If you're looking for a total driving experience, then the 1 series would be the way to go. However, if you want a nice blend of a comfortable drive to performance, I would definitely recommend the 335i. Just like the 5 series is more 'comfortable' than a 3 series, so is the 3 series to the 1 series.
I treat the 135i more as my 'fun' weekend car, because for daily driving, it's just not as comfortable. To exaggerate, it's like saying the 1 series is more comfortable than a 7 series for daily driving. Nobody will say that. So if you're looking for a good blend of comfort plus performance, the 335i will definitely satisfy.
However, I wanted to add one more point. My track car is my 335i, not the 135i. I do like the overall balance of the 3 series chassis more, that when applied to a road course, really shines. The 1 will out corner my 3 any day, but it's not always about the fastest lap time. The 1 series has more of a pocket rocket feel, whereas the 3 has the larger car, more solid feel. It's important to note that I feel this way only because our cars have PLENTY of HP; otherwise I would always prefer the lighter, more nimble car for track. I may slowly mod my 1 for track as well, so my opinion may change in the future
Also a note that for my weekend drives up mountain roads, I'd always take the 1, not the fully track prepped 3
In the end, both are great cars, and it's gonna be a tough choice! Both cars have plenty of HP, so I would not let the lighter 1 chassis be the determining mark. It sounds like you test drove both cars, and didn't give in to an impulse buy on one of them. So if the initial impulse didn't help make your choice, I'd go back to answering what kind of car you really want, and purchase accordingly. As I said above, I'm one of the rare individuals who own both, and love both