Since you didn't state your screen size, I'm assuming between 92" and 110" which is typical.
The PK301 is 50 lumens, you current projector is 1,000 lumens. You not only wouldn't be happy, you wouldn't even think you owned a dim flashlight. It's a nice toy, but it is not a real projector and entirely inappropriate.http://www.projectorcentral.com/Optoma-Pico_PK301.htm
The PT100 is no different.http://www.projectorcentral.com/Optoma-PlayTime_PT100.htm
The Vivitek is a big step downwards in quality.http://www.projectorcentral.com/Vivitek-D510.htm
You bought a solid home theater projector for the time, and now are having issues. The price you paid may have been good at the time, but you basically have no budget to replace it now. You also have LAMP issues which will continue to come up and replacement lamps which cost more than the projectors themselves.
Cheap is stupid. Period. I know people have budgets, but there are times when you just have to look at the reality of your situation and go 'This is more than I can afford' - and this is what it sounds like to me.
START with a projector like a Optoma HD65 or HD66 and plan on replacing the lamp at 1,000 hours for about $300.http://www.projectorcentral.com/Optoma-HD66.htmhttp://www.projectorcentral.com/Optoma-HD65.htm
These models are about $600-$700 and are absolute entry level for usable home theater projectors. They are a comparible model to what you have currently and should provide you with years of use without issues.
I know I'm coming off harsh, but it really isn't something I like to see when people are looking for ways to throw their money away. It's better to just save your cash for the time being until you have the money that is necessary to get a proper HT projector.
Heck, I could potentially get you a Sany Z5 for about $600 new.
But, at $300 or less, you end up with, quite seriously, junk.
Also, any purchase made, you need to be aware that the analog sunset is coming and soon you won't be able to buy a PC with an analog output, and cable boxes will turn off their component HD outputs. The quality we have enjoyed, for years, via analog cabling is going away, so buying a NEW product, which is going to not work in a year or two, is not a decision that I could possibly recommend to anyone.
Just imagine that firmware upgrade to your PS3 that then makes the component output no longer work... and your projector become immediately useless.
Just some things to consider.
- Theater, whole house audio, and technology consultation during the build and installation process in the Washington, DC metropolitan area.