They've done this with previous groups of founders.
Luckily, the choice right now isn't too hard. TechStars hasn't yet proven they can provide significantly better outcomes for their startups...they might, but they haven't done it yet. YC has definitely proven they provide better outcomes, and Silicon Valley and Boston are both better places to start a tech company than Colorado (though Boulder is lovely--too cold for me, but many folks like it). Of course, having neither backing you is probably an even worse likely outcome...so maybe it's not such an easy choice, after all.
But, if you make it to the interview with YC your odds of getting in are quite high (greater than 30%, certainly, and probably closer to 50%).
Luckily, the choice right now isn't too hard. TechStars hasn't yet proven they can provide significantly better outcomes for their startups...they might, but they haven't done it yet. YC has definitely proven they provide better outcomes, and Silicon Valley and Boston are both better places to start a tech company than Colorado (though Boulder is lovely--too cold for me, but many folks like it). Of course, having neither backing you is probably an even worse likely outcome...so maybe it's not such an easy choice, after all.
But, if you make it to the interview with YC your odds of getting in are quite high (greater than 30%, certainly, and probably closer to 50%).