The weather is probably pretty similar, although Indy might get a bit more snow than Cincy.
I'm not sure I'd call Indy "bike friendly," but I wouldn't call it bike hostile either. As Catrin mentioned, they are trying to add some infrastructure to promote bicycle commuting. I, personally, am not a fan of most of the bike lanes they've put in so far. These are roads to which bike lanes were added after the fact, so there are compromises that, in my opinion, impact safety for cyclists and motorists alike. I would prefer to just take the lane while riding downtown.
Infrastructure is just part of the problem though. The sad truth is that Indy is not a particulary healthy, active or "outdoorsy" place as a whole. Nor is it particularly progressive or green. As a life-long resident of central Indiana, I have resigned myself to the fact that the city is likely never going to be attractive in these regards. Certainly, I hope that progress can be made, but I don't think it'll ever become a Portland, Seattle, or Boulder. It lacks the naturally beautiful landscape for one thing, but I think some of it is inherent in the city's culture.
I would note, however, that there is a pretty strong cycling club here. CIBA offers a number of rides every day of the week. The weekend rides, in particular, are geared for riders of all levels and provide a great way to meet other cyclists. While the immediate city isn't exactly my cup of tea for riding, it's not all that hard to get out to more rural areas. Catrin and I both cut our cycling teeth on the northwest side of the city, and there's some very nice and relatively safe riding out there.
South central Indiana also makes for some great, albeit more challenging, riding. The hills there are similar to what you have in Cincy--so you'll likely develop a love/hate relationship with them like the rest of us. Brown, Monroe, and Morgan county offers pretty scenery for both climbing and hiking.
The city does have its pros. The cost of living here is relatively low for a city this size. For instance, my single family home in downtown Indy--with 1,000 square feet, a basement, sizeable fenced-in yard and 2-car garage--sold last May for $130k. In a lot of other cities, it would have cost over $200k. The cost of living has allowed me to spend (or save) my money for other things--like travel and bike buying.
While arts spending keeps getting cut, the city does offer some nice ameneties in that respect. There are several quality musuems, and venues for music, dance and the like. Everything is relatively accessible even if you're on a budget.
The city is becoming more interesting and diverse. Trust me when I say that it's come a long way. Downtown has become much more lively after hours. It used to be a ghost town come 5 o'clock. The IUPUI campus where you would attend school has grown immensely since I was young. It's not exactly Bloomington (IU's main campus), but it is developing a somewhat stronger campus feel. You might PM Windingroad if she doesn't otherwise respond to this thread. I believe she went to school there. Certainly, IU Med School enjoys a strong reputation as I understand it, so that's surely a pro.
Let us know if you'd like to come for a visit. I'm sure we could find some time to show you around.
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher