Sounds like you’ve found the awesome benefits of a HTPC (Home theater PC; having your PC connected to a media setup of your choice etc)! Steam has really made things very accessible for “couch” seating, large displays, and controller navigation using Big Picture mode! Don’t forget you can even launch non-Steam games through Steam in BigPicture if you wish. There are also various emulators and frontends for them made with a controller-friendly UI in mind, not to mention media players such as Kodi, Emby, and Plex that are also controller/TV friendly.
As to your question about the PS4, it all comes down to your personal preference. Do you find most of your gaming needs met via PC? Are there any currently PS4-only titles that you either can’t do without and/or don’t want to wait to see if they come to PC? If the answer to both of the above is no, you can probably move away from the PS4 overall. Of course, you don’t have to give it up completely, but simply use it for titles that aren’t on PC for whatever reason, choosing PC instead whenever given the chance to do so.
I personally feel that the PC is by far the best gaming platform. When it comes to multiplatform titles, the PC version of those titles is typically the best both in terms of technical options (ie additional graphics fidelity or configuration) and the possibility of things like modding. PC gaming also offers wider opportunities of choice. Don’t like playing on a given server or service? Switch to another! One can’t do that on something like XboxLive or PSN when they’re the only approved network, required to use the platform online. You can of course choose your operating system of preference (Mac and Linux, in addition to Windows) and some games offer support for more than one OS.
There are many options to purchase games on PC from direct from major platforms such as Steam and GOG, to 3rd party vendors (legit) such as HumbleBundle, GreenManGaming, and many others - each with their own sales and special promotions. Overall, PC games are a much better value than consoles. Even on multi-platform titles, in general the available discounts are typically much larger, much earlier, and grow larger still as the time since release elapses. This is a product of there not being a central authority like Microsoft or Sony dictating pricing, in addition to the game’s individual publisher.
Since you’re here on SRK, I assume you’re enjoying fighting games and thankfully more and more titles have come to PC. Series like Guilty Gear, BlazBlue, Tekken, Injustice, and StreetFighter, along with newcomers like Dragonball FighterZ offer a parity release and experience on PC, not to mention a thriving indie scene. Fans of Smash for instance (besides playing the WiiU variant via the CEMU Emulator if they wish) may want to look to Rivals of Aether or Brawlhalla, while lauded indie traditional fighter Skullgirls and the JP manga/doujin scene like MeltyBlood / Arcana Heart is present as well. THis is not to say anything about emulators or ports of older titles, as well as games powered by GGPO for online play on PC. Regarding hardware and peripherals, all of your controllers and sticks will likely work well on PC. Most games have built in support for XInput so there’s minimal if any configuration; some even have “Playstation style” button prompt options or at very least a mod to enable them if you wish. Some have suggested that the size of the FCG and online player base on PC is an issue but in my experience this has never been an issue. Even on older titles I’ve never had difficulty finding an opponent and more recent/active/popular titles (ie Street Fighter V, DBFZ) have thriving lobbies with many players.
Its great to see so many fighting games (and other games for that matter) from genres and developers that formerly focused near exclusively on consoles, coming to PC. If you see the value in the PC as a gaming platform and want to see continued improvements, parity launches , and ubiquitous titles then supporting these efforts by purchasing PC titles when you have the opportunity to do so is the way to go!