You’ll probably be fine either way, but I’d personally go with the channels. I wouldn’t want to see the reflections of the individual LEDs on the countertop, and a diffuser channel will also make shadows less harsh. Figure out the size of the cutout and see if there’s a channel that can fit in there and fit your LED strip inside of it.
@Emerson
Good point and good advice. Thank you.
Amari said:
@Emerson
Good point and good advice. Thank you.
Looks like you have COB strips which likely won’t show individual LEDs. I would hold it in place and check. The channels make the lighting a smaller, more concentrated beam, so no channel could be better.
@Jamie
Good to know!
@Emerson
You won’t have individual LED reflections on COB strips since the light output from the source is diffused.
In addition to the aforementioned diffusion benefits, the channels also act as a heat sink, adding to the long-term lighting efficacy.
Tatum said:
In addition to the aforementioned diffusion benefits, the channels also act as a heat sink, adding to the long-term lighting efficacy.
Thank you. I’m learning so much!
We always put LED strips in a channel, no matter where they’re installed. The aluminum channel will work as a heat sink, which I think should be mandatory, especially for a COB strip. In fact, most manufacturers recommend an aluminum channel for their COB strips. The channel will increase durability and allow for cleaning without worrying about damaging the LED strip.
We usually install our tape lights at the back of the cabinet instead of the front, but the specific conditions of the install can affect where we place the lights. Generally, the more reflective the countertop is, the more inclined we are to install the strip/profile along the back of the cabinet. With a high intensity COB strip (300+ lumens per foot) and a very reflective countertop, you can have the light reflect off the counter and end up seeing the strip beneath the cabinet while looking at the countertop. An aluminum profile with a frosted lens will mitigate this quite a bit, but it still may be noticeable.
Upper cabinets are 12” in depth, and lowers are 24”, so an aluminum profile installed at the front of the cabinet facing directly down will maximize the task lighting on the counter, because the light is directed at the center of the countertop. Again, a highly reflective counter may show the footprint of the light when looking directly at the counter. If the goal is to highlight an expensive stone slab backsplash, lighting at the back of the cabinet is best as it will reflect mostly off the backsplash. A good middle-of-the-road option is a 45-degree profile at the back of the cabinet that projects the light forward and down to maximize task lighting but minimize unwanted glare off the counter.
These aren’t hard and fast rules, and every install is different. Countertop/backsplash material and lumen output vary a lot. I recommend temping in the lights before a complete install so you can see your options and choose what works best for your needs and aesthetics.
@Rylan
Wow, I appreciate these details.
I would mount the strip in the aluminum extrusion. The adhesive on the sticky back of the strip will stick to it better and last longer. Although COB LED will give you an even look, you may want to use the diffuser to mitigate brightness as the strips are 5k.
@Denver
Thanks for the tip. They will be on a dimmer switch.
Definitely use the profiles. You already have some good long answers 
Yes, you do. The lens will diffuse the light and give it a more even foot-candle range. If you install it without the lens, you’ll get spotting.
Vale said:
Yes, you do. The lens will diffuse the light and give it a more even foot-candle range. If you install it without the lens, you’ll get spotting.
Not with the COB.
Vale said:
Yes, you do. The lens will diffuse the light and give it a more even foot-candle range. If you install it without the lens, you’ll get spotting.
Not with the COB.
They will absolutely lay down a hot line and it won’t diffuse evenly. Even outside of that, cleaning will be easier with a lens. Is it worth shelling out $5-$15 a foot? That’s up to the end user.
I’ve been designing and building LED projects since Gen one.