Yes it most definately will make a difference. Every game, e v e r y g a m e, will be downloaded to the SSD so your access times and loads times will be significantly decreased. The problem with PS3 was that you were accessing everything still from the disc, or portions of it when downloaded to system. A standard 5400rpm HDD in SATA 2 can do around 75mbps. A SSD in SATA 2, even the crap ones, can be read at 250mbps. So you are looking at triple the load speed on maps and level changes. SSD will be very worth it. A hybrid will not be as great for a PS4. Here is why, hybrids attempt to learn what you access the most and cache it. If you frequently switch games, it will not have enough storage to store your titles. I guess thinking that way…a hybrid probably couldn’t even store the used assets for a single game, being that their cache is usually 4gb.
Only true issue is if you can stomach the $300 just to match the initial PS4 storage with a SSD. My advice would to wait. SSD prices are halving very rapidly, somewhere close to a yearly basis. Around 2-3 years out would be a great time to buy a replacement drive.