My father owns the xi5, so I can comment on it since I've spent a fair bit of time with it.
Pro's of each:
Talon: Boat doesn't spin if you have two of them and good bottom contact
Talon: Easier on battery
xi5: Literally keeps you exactly on a spot, regardless if it's a river or 25+mph winds. It's amazing.
xi5: Has a key fab. You can control the motor from the back deck if you want, so from shore if you're forced to launch the boat by yourself. See con section for this as well.
xi5: Depth isn't an issue in regards to spot locking.
xi5: It has cruise. Point the head the direction you want and lock it. It will run and take you that way. Need to change course? Just bump left or right on the key fab.
Con's of each:
Talon: Adds weight to your boat, hurting your top end speed (tournament guys care about this)
Talon: If you fish with a buddy or co-angler, it makes casting from the back deck very tricky
Talon: Only works in shallow water
Talon: Doesn't work well in rocky bottoms. Your boat will scoot along until it can grab into mud or sand.
xi5: The foot pedal is absolute garbage. It works completely differently than a standard cable drive motor. It makes navigating around tight things like docks, islands, rocks, wood, etc. very difficult. You're better off using the key fab, which requires at least one hand to use. Which means to try to cast/fish is impossible with a moving bait that requires two hands on your rod/reel. My Dad and I have both tried for multiple days to operate that foot pedal, and now we don't even take it out with us because we find it that useless.
xi5: It keeps your trolling motor head in one spot, not the entire boat. If there is river current or wind, the back end of your boat will spin with that. Regardless of it doing that, the motor head stays at one spot. I've locked down next to a single weed stalk on a flat in 25 mph winds for an hour and fished the same spot. I never moved away from that single weed stalk.
Overall, I'd say the talon is great for shallow water, and bass fishing around tight spaces. The xi5 is good for open and/or deeper water. Do you want to lock yourself on top that school of walleyes on that 25 foot rock hump? Do you need to stay pinned over top a group of smallmouth on Erie when there's 3 footers? The xi5 is great for that.