In my opinion, there aren't many perks that are really duplicated. Priority Pass and PreCheck/Global Entry are the only ones that come to mind (unless you count certain non-transfer redemption options). I like having both the Platinum and the CSR because the Amex airline partners work better for me, but Amex points are nearly useless for me for hotel redemptions. Chase UR points have some great hotel transfer partners, and Southwest transfers are great if I need a cheap flight (usually when I'm booking flights for someone else or all other options are too expensive). The CSR's main advantage is that you get to combine all of your UR points, and UR points are easy to obtain and have a high value. Combined with the no-AF cards of Freedom and Freedom Unlimited, you get 5x points on rotating categories (this quarter is particularly good), 3x points on travel and dining (go with the CSP if you don't spend a lot here--you still get the biggest perk but don't have to shell out the high AF up front), and 1.5x points on everything else. This structure pairs up farily closely with the EDP Amex card, for what it's worth, but the categories are different, which means they complement each other well. Chase UR points also have a convenient minimum value for travel when you use the Chase travel portal.
The CSR doesn't have a lot of non-point perks. Some people value Priority Pass, but so far I haven't found Priority Pass lounges to be the most convenient for how I travel. My airport only has a SkyClub lounge, and when I fly Delta, the SkyClub lounge is almost always the closest to my gate. Check out the airports you frequent most (or where you want to go most) and see what Priority Pass lounges are available. If they're not convenient or you're not really into them, then you shouldn't value Priority Pass that highly. The PreCheck/Global Entry perk is worth face value, but it only works once in every four years (and a PreCheck/Global Entry membership lasts for five). And I don't rent cars much, so to me the car rental perks aren't so much a perk as much as they are a nice bonus if and when I need them. The most valuable non-point perks for Chase are the travel insurance policies. Primary car rental coverage is standard (Amex charges extra for primary coverage), travel delay insurance applies when you put only a portion of the trip on the card (the Platinum doesn't have this), etc.
By far I have found the Platinum perks to be more exciting (except for the airfare credit--that is where the Amex program stumbles most; Chase's travel reimbursement is better, end of sentence). I love the access to SkyClub lounges. Travel will never be the same for me, and I can't go back to crowded waiting areas and outlet deserts (LaGuardia anyone?), and Centurion lounges are the best available. Amex offers can save you a lot of money, depending on which offers are available and where you spend your money. (However, since 2015, I believe I've saved $60 on cell phone/cable bill offers alone). The automatic gold status with SPG automatically matches with Marriott gold status, which has gotten me lounge access and executive floor upgrades at every single Marriott I've stayed at since getting the card. I don't stay in Hilton hotels often, so I haven't taken advantage of the hilton status perk.
The sticker shock is what gets most people for these cards. Together they're $1000, which to most people is insane just to have the ability to spend money. But, if you can use the Chase $300 travel credit (which covers basically any travel expense), the $200 airline credit (which usually works for gift cards, with certain conditions and exceptions--see FlyerTalk if you have questions), and the $200 Uber credit (which I use for UberEats most months), then the out-of-pocket expense is only $300 for everything I've described above. Whether this $300 out-of-pocket expense makes sense for you to spend is highly dependent on your travel preferences and frequency and income.
In general, if you are looking to make travel more affordable and you want peace of mind when you travel, choose the Chase CSR. If you're looking for elite experiences, choose Amex Platinum. If you like Delta and Hilton, lean towards Amex. If you like United, Southwest, Hyatt, and Marriott, Chase points will help you pay for them. If you want both, it can definitely make sense to have both.
However, remember that Amex SUBs are once in a lifetime. You may not find the 100k offer again/when you want to. They're not offered all of the time. If you decide you want to apply for the Platinum in the future, you may find yourself having to choose between signing up for a worse SUB or waiting indefinitely for the 100k offer to come around again. The CSR SUB is pretty stable at 50,000, and it is highly unlikely that Chase will offer 100k points anytime agian in the near future.
Edit: I should add that for those who are comfortable with booking airfare using airline partners, you can unlock value for both point systems in lots of unexpected ways. I'll let other people who know more about this than I do help explain how this affects the decision-making process if you're interested.
Personal Cards: Amex Plat | Amex Delta Res | CSR | Citi AA Exec Business Cards: Ink+ | Amex BGR
