A 5.7 hemi will certainly cost more but it will have at least 100 more HP if both are installed basically stock. To get the 360 to the same power level would require head porting/replacement, cam, intake... that will bring the price a lot closer together.

If you want to go farther in the future the hemi offers some really easy upgrades to get more power once installed, cam swaps wake em up a ton, BGE or apache heads are reasonable priced and offer insane amounts of flow.

A little more direction about where you want to end up would help.