Good alternative to Golite Jam 50L?

If you want a frameless pack comparable to the Jam, some popular option are:
MLD Exodus
ULA CDT

If you want a pack that is a similar size and weight as the Jam, but potentially more capable (ie. has some sort of simply frame system), then great options are:

ULA Ohm
HMG Windrider
Gossamer Gear Gorilla

All three of those are outstanding sub 2 lbs packs that make an excellent choice for a UL hiker who has one pack.

What kind of base weight are you dealing with? And what price max is acceptable? There are a lot of options around, and a great many packs, even with suspensions, that are lighter and just all around better than a Jam 50. I'm a big fan of ULA packs. The Circuit is outstanding, and by removing the unnecessary parts you can drop 5+ ounces very easily. So for a 4ish ounce difference than a Jam 50 at 30 ounces (which is ABSURDLY heavy for a "frameless" pack), you could get an incredibly durable, beautiful backpack with possibly the best load support in its class and price range. About double the price of the Jam, but 10 times its superior in every other area. (Obviously I am heavily biased towards ULA, please do further research) :)

If you can fit your gear into it, the ULA Ohm 2.0 is a hands down winner for me. And at stock weight of 29 ounces, its already lighter than the Jam 50 even before removing all the extras.

About the same size as the Gorilla, it has an exceptionally comfortable suspension. Virtually all the weight is transferred to the hip belt. It will hold a BV-500 vertically plus a lightweight kit. I'm using this pack for a SOBO JMT hike next month.

I have more than enough gear to cover me, but it is all geared toward mountaineering, so not the lightest.

I stay around 30# for a 2-3 day alpine climb with 2L or water and food, so I know I can stay well below 30# on a 5-7 day hike not having to carry crampons, ice axe, harness and rack, etc.

I have a Black Diamond Speed 55 pack that wold work in a pinch and I can strip some weight from it, but shaving a pound or two off with a different pack would be nice.

Here's my gear so far for my attempt at going light:

TarpTent Moment DW (Haven't ordered yet)
Enlightened Equipment 20* Quilt
Thermarest NeoAir XLite Regular
Thermarest pad cover
Nemo Fillow Pillow (My luxury item)

Trangia Alcohol Stove
HEET
Snow Peak Titanium Trek 700
MoJo pot stand
Long Titanium Spoon

Marmot Super Mica shell
Marmot Precip Pants (?)

Still working on the rest, but I think this will be the bulk of my weight along with food and water. The hike I am planning is close to home, and has several opportunities for drops of needed, but I was hoping to carry everything start to finish.

Just curious. If you were set on the Jam, what drove that decision? If the Jam is the pack of choice, why would you consider something different when the only issue is color? Is the color critical for blending in or something where color is important to your hike?

Not having any clue on UL packs, I was leaning towards the Jam from reviews and comments.

It might sound superficial, but I'm not going to drop $100+ on a purple backpack. Clashes with my eyes… :)

For now, I am going to plan on using my Speed 55 pack stripped down. I should be able to get it down under 3# without having to butcher it. For my initial long hike, it should suffice.