The new SHIELD TV makes a few changes to the formula that earned the original a spot as the uncontested king of Android TV. It's smaller, simpler, and comes with new accessories. The "updated" SHIELD Pro is a bit less evolved. It's still the same size as the original, and it's shipping with the old SHIELD Remote. That could be a plus or minus, depending on your perspective.
The original SHIELD Pro bundle didn't include a remote at all (neither did the regular one). So, simply having a remote included is new. The remote appears to be identical to the 2015 version you could buy separately. It has a headphone jack, a rechargeable lithium-ion battery, and no IR.
The remote included with the new SHIELD has coin cell batteries that have to be replaced, but last a really long time. The old remote would run a week or two on a charge. The new remote also lacks a headphone jack, but the updated controller still has one, so you don't lose that feature completely. The new remote has an IR blaster so you can control other devices with it. The old one is just Bluetooth.
Some might say the old remote is better than the new one. It's not that clear-cut, though. You don't have to deal with the batteries in the new one as much, and the IR blaster will be something many appreciate. Just something to know before you buy.