Probably even more info would be helpful. But here are some considerations:

Domestic Travel:

You'll get different opinions of course, but I think Delta is pretty good for its elites, of which there are 4 levels: Diamond (125,000 elite miles/year); Platinum (75,000 elite miles/year); Gold (50,000 elite miles/year) and Silver (25,000 elite miles/year). As a Platinum, I think Delta is very good domestically. Most of Delta's planes have a first class cabin and my upgrade percent is 100% on the year and was around 90% for last year (but yours may differ depending on where and when you are flying). And, if you get the upgrade, Delta offers a pre-departure beverage which I think is nice. Also, most of Delta's planes are equipped with WIFI (for a fee) and many have in flight entertainment.

Other perks that I get value out of as a Delta Platinum include free 'same day changes' and free changes to award tickets. Also, I get (as do Golds and up) a 100% bonus on SkyMiles (not elite miles) earned from flying.

International Travel:

This is where Delta is pretty abysmal since there are no complimentary upgrades for elites on international flights. While you can select as a benefit 4 or 6 System Wide Upgrades (if you reach Platinum Medallion or Diamond, respectively) that can be used to upgrade an international flight... they can only be used to upgrade very expensive Y/B/M fares that generally cost as much or more as a business class ticket. Also, since Delta is a 2 cabin carrier (i.e., economy class and business class) you can not redeem SkyMiles to book First Class tickets on any 3 cabin Sky Team partners (e.g., Korean)... business is as good as you can get using SkyMiles.

Earning Status on Delta:

Here's something else to think about: with Delta, through the Amex Delta Reserve card, you can earn 30,000 elite miles/year without flying. That means it only requires 45,000 additional elite miles to reach Platinum status. And 45,000 miles (plus the 30,000 from the Amex DL Reserve) provide more benefits being a Platinum on Delta than most will get from just earning 45,000 elite miles on another carrier.

Personally, if I flew 100k and up a year so that I could achieve top elite status on another carrier, I might consider switching to another carrier. I'd really appreciate a better alliance with first class cabins to redeem miles on (like Swiss or Cathay or Lufthansa). With Delta, Korean business class may be as good as it gets. I'd also love complimentary upgrades on international flights or upgrade certs that actually have value (which I know at least AA provides its top elites). But, for me, I simply don't fly anywhere near 100k annually, so those perks are out of reach for me on any other carrier and I'm happy being a Delta Platinum.