Grand Theft Auto: Episodes from Liberty Cities combines both the of GTA IV's expansions into one disc, primarily for players that prefer to have some type of physical media over a digital download for whatever reason. There's not much draw to owning a disc copy over the digital versions for any other reason that I can see, outside of the addition of a few new radio stations (one of which is a Vice City themed one, which is certainly a plus), but on the flip side you also lose some stations too, so you're kind of breaking even here depending on taste. Outside of that, the content seems to be the same between the downloads and the disc, but it is nice to have the option available.
GTA 4: Complete Edition is not a remaster, but it does do some pretty cool things for PC gamers including finally removing Games for Windows Live.
"Amazon has added new game deals for this weekend. Deals include Xbox One 500GB Console – Name Your Game Bundle $249, Metal Gear Solid V: The Phantom Pain $10, Homefront:The Revolution Goliath Edition $100, Helldivers Super Earth Edition $15 and lots more!"
"Amazon has added new game deals for May 26th. Deals are Overwatch - Collector's Edition $95, Dragon Quest Heroes: The World Tree's Woe and the Blight Below $30, Grand Theft Auto: Episodes from Liberty City $5 and lots more!"