UST or Ultra short throw refers to a projector that can physically sit inches (say 7") away from your wall and will project via laser technology (no bulb) in a 100" display. Move the UST projector back to say 17" and now your viewing size is 150". UST can be placed on a table in front of your wall OR UST projectors can be mounted on the ceiling and projected. Lumen count on some UST can start from low 2,000 lumen to well over 8,000 lumens but expect to pay $$$$$ just for that solution.

Here are a few videos talking about the UST projectors that have changed the game for other projector manufactuers (Epson, Optima, to name a few). My projector replacement will be of this variety. 4K output, ease of menu, auto focus, short distance to wall, ceiling mount or not (flexible design) and will work in your living room. At that point it is all about your design and location. 

Vava 4K UST review

Vava projector cost

https://www.indiegogo.com/projects/vava-4k-ultra-short-throw-laser-projector?gs_variant=gs#/ 

Xiaomi Mi 4K UST laser projector 2019

Long throw projectors hang from your ceiling and is mounted mid or all the way back in your room and will project through the light or dark in the room to the wall or screen on the opposite side. You really need a projector with high lumen count to project that through your room and onto your screen/wall. So expect about 3,500 and up for that to be a workable solution.

A very good site to research is: https://www.projectorscreen.com that will answer pretty much everything about projectors, screens, etc. 

ALR (Ambient Light rejection) refers to the ability a wall (painted) or from an ALR screen to reject the ambient light in your room while watching sporting event, concert, movie, etc. You can watch what you want with the lights on. ALR can be purchased in a screen or from painting your wall with ALR tech paint. Projector screen link above shows you some UST projectors AND ALR screen or ALR wall paint. There are youtube videos of ALR paint and the good ones will show a demo with lights on, while allow you to watch without any eye strain. There are some that even show the technology outside, in ultimate ambient light. 

DIY gives you the ability to build your size screen for really cheap (there are DIY videos out there) with various screens (spandax to purchasing an ALR screens). DIY is a very economical way to get what you want.  Right now, I'm in a research/design phase of what I want to replace my existing 100" screen. I only paid gas money and my time for acquiring this screen, which was from a board room in buckhead. Hey, it works and is good for now. There will be an upgrade path though. Just have to iron out details and save for the screen. 

So TV over a projector?

For my Home Cinema room, I'm a strong lean for DIY 150" ALR screen or ALR paint on a smooth wall with a 1.5 or 2" masking around the 150" wall. IF I go this route, I will most likely thin coat a sheetrock wall, apply a prime paint (don't have to do this) then apply a gallon of ALR paint on the wall.

Since I have the capability to have a TV in my family room (none right now), I can also use that space for UST on a motorized screen or not (again, a very flexible design). Cost for either solutions, less than 1,00.00 and I get a massive screen.  I know at CEIDA 2019, there were massive screens, larger than 150" but do you have over 10k to spend?  

Here is a good screen company for DIY: https://www.carlofet.com 

DIY video

https://www.youtube.com/watch?v=Ao18_Ciq3z4

In all, I can get my size sreen (150"), my 4K projector and all taxes, labor, time, etc for about 3,000.00. Not bad and I can have that in 2:35 to 1, 16:9 layout. Right now, TV, even 4K TV can't touch screen size, flexiblity for that price point. IF anyone is still in school, don't bother and focus on school, getting by with what you have already. After the education years, then start planning for and investing in such tech. Staying out of debt is more important IMO than keeping up with the Joneses. 

Hope this helps.