I'm close to purchasing one of these three camera's the hmc 150, hm100 and hpx 170. I'd use the camera for filming lectures, sermons, occasionally a small time commercial or band video. Has any one used these and could you recommend one?

I Rented a HMC150. I loved it. It is a better camera with much better layout and controls.
It was just too big for what I needed.
Only negative (maybe) was the AVCHD codec.

I am really starting like my HM100 now that I am learning it and based on Tim's DVD.

Also, after reading the reviews of the HMC40, I am really glad I have the HM100.

I think a very usefull way to distinguish cameras is by chip size. 170/150 have 1/3" chips and the hm100 has 1/4" making it more in the MHC40's realm.

So, the question is how good low light performance do you need? All other things being equal (which they never are), a larger chip gives better low light performance.

Physical size is another: hm100/hmc40 are noticably smaller than 170/150.

Personally, I absolutely love the waveform monitor on my HMC150--also available on the 40.

My exact thoughts- HMC150 has real controls, it's basically a copy of DVX100. But after hauling HVX200 and GY-HD100 in the mountains, I decided I need to go small to get the shots I need and HM100 fits the bill. I had to modify the lens via 2 adopter rings, so it will accept Cokin P attachment and fisheye lens.

So to answer your dilemma you'll have to ask yourself if weight, size, controls are very important, or you need something small and light.

One important note, HM100 has uncompressed sound- which is a HUGE advantage, as you don't need to worry about sound quality.

Right now HM100 is just about 3K at B&H with free shipping, much better price then 3.5K early on. On that note I am bit disappointed and last year buyers were told that 3.5K street price was firm and retailers were obligated not to sell it below it. But what is a forced loss for me is a gain for you- if you are on the market for this camera.

Wouldn't comparing the HM100 to an HMC40 make more sense (than comparing to HMC150 or HPX170)?

I'd like to know if anyone has shot some real good side-by-side image quality comparison footage (comparing HM100 and HMC40).

I thought the HMC150 and the HM100 would be a good comparison and did compare them both when I got my HM100. I loved the look of the HMC150 images and I really liked the button layout. It seemed more like a real video camera for professionals where the HM100 seemed more like a mix between a pro and consumer model with the iris, shutter toggle thing on the back.

I bought an HM100 because it produced easy to use Quicktimes instead of AVCHD which is a pain to convert. I am ready to go with an HM100. I could shoot for 3 hours and then only take 15 minutes to copy that video. With the HMC150 it would take maybe 3 hours maybe a lot longer to get the AVCHD into ProRES. I also thought a little more dynamic range could be pulled out of the HM100 and recorded as flatter image for later grading.