The spikes on my pair of True's from last season wore down while the rest of the shoe was in near new condition. If you're looking at it from a strictly cost perspective, shoes with replacement spikes will last longer and give you more value for the money.
Money aside, the True shoes and Ecco's with permanent spikes are much more comfortable than the shoes I own with replacement spikes. I wear my True and Ecco's to the stores and then hit the range without having to change shoes, I'd never do that with my traditional golf shoes with replacement cleats.
Golf wise, I prefer True's and Ecco's for the range and on courses that aren't too hilly or when the course is not muddy. On hilly or muddy courses I prefer the replacement cleat shoes as I feel they give me more grip and support.
Hope this helps.