It's kind of like comparing apples and oranges, they're two completely different setups: .30-30=mid weight bullets, mid velocity fairly lightweight levergun, .243=light weight bullets, high velocity, decent weight boltgun, I'd say the only similarity is the fact that people often claim similar range capabilities of the two-which very much so under-rates the .243win, and only slightly so the .30-30win.

It really depends on personal preference: Do you prefer a levergun or a bolt gun? I really love leverguns, but I'm not a huge fan of the .30-30 (I firmly believe that a .44mag is superior to the .30-30 for hunting-ask and I'll explain), I'd probably get the levergun even still just because they're so much fun to shoot...that said, I really love leverguns, and just for hunting only deer at only the range you suggested, the .30-30 will be better IMHO...If you're looking for a varminting rifle then the .243 is your choice.

The .30-30 will likely (not guaranteed) put your deer down faster than the .243, big bullets usually give faster kills than small fast bullets-USUALLY. As I said, I'm not a fan of the .30-30 when compared to other typical levergun cartridges, and I am a huge fan of the .243Win, but then again I'm more a fan of leverguns than boltguns...If I were to use this gun only for deer to ONLY 150yrds, the .30-30 would be my choice, there's no reason to limit the .243 bolt gun to 150yrds for deer though, it's good for probably 100yrds more at least with a good scope, and it really excels at varmint hunting out to 600yrds-you didn't ask about that though.

If I were buying my first rifle, it would be a .243win or WSSM, if I were adding to a firm battery to include a gun to be used ONLY on deer to 150yrds, it would be the .30-30.