I bought my ATP at Sheble Aviation in Kingman, AZ back in 2005. It's probably the best thing I've done in my aviation career except for switching to logbook software (awesome).
I originally got the ATP because the company I worked at didn't give it to their pilots since they didn't have FAA approval. Then they would pay you back $1500 after you upgraded. I ended up leaving that company before upgrading though.
Having it allowed me to interview at a fractional and an LCC; I got hired by one of them and now fly an MD-80 with a pretty bright future. Meanwhile my other friends who didn't get their ATP are still at the regionals waiting for they day they are offered upgrade.
If you want to interview at any fractional, you must have it. If you want to interview at a major or LCC, all prefer it, some require it. You paid for all your other pilot ratings and certificates, why question this one? A type rating is different; it can only be used for one type of airplane. The ATP can be used to fly all types of airplanes at all companies.