Reviews of specific carving products by those who've used them.
I hang all of my pumpkins from the house and trees so plug in strands of lights or individual bulb lights don't work for my set up. So I use battery operated lights for my foam pumpkins and a few real ones.

Pumpkin Masters lighting strobe light.
Out of 10, I have 1 did not work when opened
Of the working 9, 3 are so dim (even with new batteries) they look terrible in kins
Of the working bright 6, they look good. Not great, just good. I think best in pumpkins carved with words
Bright white light that flashed very fast and not on a regular blink rate
2.5 of 5 stars
PM11017 Lightning LED Strobe vio by marc 1971, on Flickr

Pumpkin Perfect Morphin Pumpkin Lihght
Out of 8 I have, 2 did not work when opened. Cheply made
Of the 6 the rest blink from 3 different colors pretty brightly
Red, Blue, Breen flickers at a regular rate. They look pretty good
2.5 of 5 stars (would have been 3.5 if they all worked)
morphing_pumpkin_light by marc 1971, on Flickr

Pumpkin Light
Don't recall the pricing
Continual shifts between 7 colors at a regular rate
I have 2 and they work well, although one died this year after 3 years of use
Bright and looks great in pumpkins
Also made in a purple casing
4 of 5 stars
41piUAXBOGL__SL500_SS500_ by marc 1971, on Flickr

Strobe Pumpkin light
Fast blinking strobe light.
Very bright, random flicker
Cheaply made, the plastic bubble the lights are under is what you click to turn on. Often turn on by itself at the slightest bump.
Have not seen this one on sale for a couple years
3 of 5 stars
00191874_interactive_a by marc 1971, on Flickr

Early version of the color changing Pumpkin light
You can select which color combo or single color and leave on that color or rotate
Very bright and looks amazing in your kin
Not sure this is available anymore
4.5 of 5 stars
177863_dt by marc 1971, on Flickr

Artificial Candle Pumpkin Light
Looks like a candle flickering
Farily bright and natural look
I have 1 and it has been working for years
Looks very good, wish is was a tad brighter
Not seen on the market for a while, probably can get online
4 of 5 stars
01039551_interactive_a by marc 1971, on Flickr

Color Changing Pumpkin Light
Similar to the morphing light in function but a more reliable light
I have 2 and they work very good
Good lighting and rate of change of colors
Colors are somewhat weak, think lighter white saturated colors
3.5 of 5 stars
16350-LED_Kuerbis_Licht-Halloween_Zubehoer-Kuerbis_Licht-Horror_Zubehoer-LED_Licht-Halloween_Lichterkette by marc 1971, on Flickr

Pumpkin Maters Strobe light
I have 4 of these and they are very strudy
Only lights that use C batteries, rest use AA or more likely AAA
Very bright, flashing bulbs to imitate a candle but does not remotely look like a candle when on
However I do like the way the pumpkin looks when they use this bad boy
Con - it's massive. No small cut to get this in the bottom or side. It's huge.
4 of 5 stars
7E2058BB by marc 1971, on Flickr

Sienna Battery Op 20 LED timer lights orange
A new find at my grocery store, 3 of 3 work great
So bright I have to wear shades. I'm not kidding I tossed this in a small foam 'kin to test and it was shining through the wall (gemmy type)
Incredibly bright, looks amazing in pumpkins and at a good price
I haven't even tried the time (6 hours on, 18 off)
5 of 5 stars
I'll be looking online for better deals and different colors for the future (below is not the package I got mine in, close but and orange background
32_4508875_3 by marc 1971, on Flickr

May be next I'll show them in action with a "control" pumpkin....after Halloween...