Is this huge of a screen worth buying?

Stewart screens are ( in my opinion ) better. However, that is a really big electric screen. Electric screens - especially tensioned ones - are just more expensive !!

Is there a dramatic difference between a Firehawk screen and a Da-Lite matt white screen? Depending on your room and viewing conditions, yes, there is, in my opinion. I originally started out with a Da-Lite matt white screen like yours. It washed out too much in my room lighting - making the picture less than stellar. The Firehawk helped with room reflections and the picture looks much better.

FYI - you can't buy a manual pull down Firehawk - they don't make one. But for the best screen prices - call Mike or myself.

And by the way, that screen is so big, that the $ 11K price tag should be no problem, 'cause your going to want an $ 80K 3 chip DLP light cannon to light it up with.

Babka - I think Craig makes a very good point. I am in a similar boat. Here is my summary of what I have found:
a) At a diagonal of ~140" and below, there are several sub-$10k projectors including the Panny that can do the trick.
b) When you start edging towards 150" and above diagonal, the cost of the projector starts jumping exponentially if you dont want contrast or screen ft-lamberts to suffer. You rapidly come to the conclusion that to have the same contrast and brightness at a size of ~140-160" diagonal, that you are used to with a JVC or a Panny at sub 140" (diagonal), you have to get either a mid end DPI or projection design or something in that range - which is starting to touch $20k. If you want to go even larger to 186" diagonal as you mentioned, with o compromise on contrast or brightness at all, you pretty much are talking a Sim2 Lumis or a DPI Titan or projectiondesign aviello. and even a Sim2 Lumis will probably struggle at 186" diagonal although I think some on the forum do have a Sim2 driving a screen roughly that size.

I think the size of the screen can depend on your room as well. My room is bat cave with dark walls and ceilings. I have a $1000 benq w1070 projecting on to a 150" screen from 15 feet back and I love the image! I wouldn't be a afrraid to go big, just make sure your room and PJ can handle it! Check out POST # 2486: http://www.avsforum.com/t/1435626/benq-w1070-dlp-full-hd-3d-ready-with-lens-shift-for-1000/2460

True JoeBoy73. However, your BenQ 1070 is an exceptionally bright projector. The OP's Panny AR100u is not - " Lumen Output (Eco Lamp, Cinema1): 601, vs. Full power (Cinema1): 798 " http://www.projectorreviews.com/panasonic/pt-ar100u/performance.php

So, on a 150" diagonal screen, with a screen of 1.3 gain ( like a Stewart Studiotek 130 G3 ), he would start off with 15.49 foot lamberts with the fan in high ( noisy, loud ) or under 12 foot lamberts in Eco Lamp with a Panny AR100u. With your BenQ 1070, starting at 1166 lumens in Eco mode and best picture mode ( http://www.projectorreviews.com/benq/w1070/performance.php ), you start with over 17 foot lamberts with just a 1.0 gain matt white screen.

Always do your research on your projector brightness / performance ( forget the factory specification numbers ) before deciding on a screen material or size.

Unless you don't care how dim the picture is ..............!
Edited by Craig Peer - 2/26/13 at 9:48am

LOL...man I wish I had a rail system! Unfortunately....I had to learn the hard way with my previous PJ. I just picked up some outlet panel covers and painted them the same color as my ceiling. Have you used or seen DLP tech? It's a great picture, but there are some side effects that can bother some people.