Lamp Life and Replacement
This is basically a cost of operation issue. First I should note, that just because a projector claims a 2000 hour life (for example) don't necessarily expect it to last as long as claimed. There are several reasons.
1. Manufacturers tend to be optimistic - it's a game - "who's got the longest lamp/lowest cost of operation
2. The lamps themselves are not that consistant. A significant percentage of 2000 hour lamps may fail at 1500 hours or less, and others may last 2500 or more. (however must projectors will not let you significantly exceed the claimed life - what does that tell you).
3. You have to take proper care of your projector. Want the lamp to last half as long as best possible - its easy , don't clean your filters. Most projector manufacturers want the filters taken care of every month! As they clog, the projector starts running hotter, and failures happen sooner. So it's up to you, to get maximum out of your lamp.
Each of these projectors has a low and bright lamp mode, however in some cases, the setting is manual, and in others it is tied to other settings. For example, with the Optoma H27, if you want to run "AI" (artificial intelligence) on, the lamp will automatically be on bright, so it can dim the lamp as needed for darker scenes to maximize black levels. With the Epson lamp is automatically in low power on the Home Theater Black 1 and 2 settings but full power on all the other settings...
Officially, here's how they are rated:
Optoma H27 - Full power: 2000 hours, 3000 hours in low power (see below under brightness, about best modes and "AI").
The projectors range from a claimed 850 lumens (Optoma) to 1200 lumens for the Epson, but that doesn't give you a full idea of how they peform.
In reality, all four projectors were extremely close in their best (and dimmest modes), with the Optoma being the least bright, measuring just under 300 lumens, the other three: BenQ 388, IN72 359, Epson 386, Optoma. Note, the Optoma produces close to 400 lumens with AI engaged, but, that also kicks the lamp into full power mode when needed.
So, you will find the Optoma to be just a little less bright in low power, but comparable with AI. The brightness differences between the other three are really only enough to be noticeable in side by side comparisons.
I normally don't meaure the brightest modes, as we focus on movie watching, but for your enlightenment, the Epson definitely measured the brightest, which may make some of you choose it if you are heavy into watching sports or gaming.
After that, the BenQ and InFocus stay pretty close, with the BenQ maintaining a slight advantage, and the Optoma in brightest mode remains a little less bright (understand a 20% difference in brightness is very slight. If you were viewing a projector, and left the room for a minute and came back in, and the projector was then set to produce 20% less lumens, it is extremely unlikely that you would be able to tell at all. But if you watched the setting change, you would notice a small drop in brightness. (Imagine being in a room with five 100 watt lights going, and then turning 1 of them off - that's a 20% reduction, but the room lighting would only be slightly dimmer.
Bottom line on brightness - for maximum brightness - for non-movie watching, the Epson is the brightest, a step down, the BenQ and InFocus, lastly the Optoma.
For best quality movie watching, they are all about the same, since the H27's best mode has AI enabled.
General Comments - Inputs
For a photo view of the input panel of each of these projectors, visit the first page of their respective reviews (the links are provided below).
Inputs: Some variation from model to model. All have S-video and composite video, but we're more concerned here with the higher resolution inputs - component video, digital, and computer analog - consider:
Optoma H27, has a digital input (DVI) that can take either digital, or a computer signal, plus one additional computer input (analog) and one component video input. Thus you could hook up a digital source, a computer, and a high quality component video input.
InFocus IN72 - The InFocus takes top honors, by a slight edge. It offers their proprietary M1 connector which supports either digital, computer or component video. It also has a separate HDMI (digital input), and a component input. Like all but the Epson, the total count is 3 high resolution inputs, but only the InFocus and the Optoma can use one input for a digital source and still hook up an analog (normal) computer.
Epson Home 20 - This is the only one of the four projectors that lacks a digital input, which is too bad, as that's the direction things are moving. From a practical standpoint, however, a component video input is roughly comparable. The Home 20 has one component video input, and a computer input that can be used for an analog (normal) computer, or for a 2nd component video.
BenQ W100 - This projector is fairly well connected. It has a DVI for either digital input or a computer input, plus two sets of component video. One downside. If you want to hook up a computer, you won't be able to also have a digital source. (external, optional swtichboxes or special cabling, notwithstanding)
We could go on, and on, but remember you can visit the separate reviews of each of these projectors to read more details about each: