Yes there are others, and yes some may have some more custom items available.
Some may have some security features, and some may have all or none of these.
My personal recommendation is and has always been PotableApps.
Of all the portable applications software and loose communities, PortableApps is the tightest and most supportive.
A lot of portable Beta testing takes place at PortableApps and the finding's are readily available through their forum.
I would also note that most other portable Launchers have a system support for PortableApp's installer.
Well lets face, most of the popular Portable Launchers base their work on what PortableApps has built.
I have never had an issue with utilizing portable software from other resources with the PortableApps Launcher.
As an IT Administrator, and someone who travels a lot, it is an excellent idea to have something.
in the past I have worked at Correctional institution that would not allow a Laptop, but would clear a portable drive.
The advantage of having your own needs to yourself, and leave little to no footprint is invaluable.
PortableApp has always been there for me, and drop dead reliable.
I create Portable Application drives locally for several local Business. A couple of customization tweaks(Company Logo and coloor ETC.), the agreed upon software, and encryption for the stick.
I charge $20.00 plus cost of drive. Having developed well over 1300 of these, using PortableApps, last year alone; well you do the math!
Now understand the $20 fee is for the customization and loading Labor) of the software. I do not charge for portableApps or the software supplied as it is all free. I also offer a years upgrades for an additional $5 (Of which I carry a constant 2700 -/+), this fee is to have the drives brought or mailed to me and I update all the free software, again only charging labor - not for the software. I notify my client of upgrades to software available via e-mail to an appointed contact person.
Now I am guestimating more than 5000 sticks sold to companies over the last 3 years all with portableApps, and all these have one thing in common; No complaints, and no break downs. Atleast on the software end.
I have tested a lot of the Apps out there, and have found many lacking, or they are too much, with little explanation on use, but in my experience PortableApps is the most stable and intuitive.
For all the options available and all the other portable launchers out there, I say go with PortablleApps and you won't go wrong.
On a personal note:
On my 16G OCZ Diesel
I Run Ubuntu, PortableApps, and a good number of diagnostics
So Yes I use it, and I openly support it.