3. Lack of any Secure Folder solution.
Protected folders didn't work?
5. Very awkward to change port configuration without having to adjust most other modules such as phpmyadmin. Helm just requires one setting change.
Which port settings?
6. The fact that Plesk insists on running on secure server (SSL certs aren't cheap you know just to host a control panel). This should be optional.
Have you tried changing or adding a listening port for the control panel? The Plesk cp basically runs on its own copy of apache with it's own settings which can be changed. Last time I checked, listening was only setup on 8443, but I would assume you could add another port for non-secure? Usually 8080 is the default standard alternate port, but this is currently used by tomcat. I would think you could use something else though.
7. No built in auto-signup script (quite a serious ommision if you're using it for a hosting company, and no, I'm not paying for HSPComplete to gain this function when Helm give it away completely free bundled within the control panel (besides, HSP only runs of Unix boxes and mines an NT server).
Most cp's don't have a built in signup script from what I've seen. So far, the only ones I've seen that do this are helm and h-sphere. Every other control panel I've used requires a 3rd party billing system to generate signup pages. Most don't overlap businesses and only provide the control panel.
9. The lack of any integrated Anti-Virus support! Where is Dr.Web for Windows?
EDITED - I just checked, it looks like Dr Web is available now, but it's too late, the other problems put me off Plesk enough to dump it anyway.
From what I hear, dr web isn't the best solution anyway and it's only a 15 mailbox free license. Most control panels don't add antivirus automatically and require this to be an additional 3rd party software anyway. It's not too tough to install something else which is what most hosts do anyway.
Btw, after using helm, I have to say that I prefer plesk over helm because:
1. The typical single server helm license provided by most datacenters doesn't allow for an easy solution for a secondary dns so hopefully you don't need this option or you can afford to implement it.
2. helm is significantly more confusing than plesk with server administration, setting up the server, resellers vs end users, etc.
3. Also, when we got our server, the setup wizard didn't even work so we had to manually go through and configure half of the stuff on the server to even get it to work.
4. Helm didn't come with some pieces of software which plesk already does so we had to manually find some things such as a mail server, anti-virus, etc and install them ourselves.
5. In addition, an important feature for us was that we have a single control panel for windows as well as linux, but helm is windows only and doesn't support linux.
Helm looks pretty, but as for functionality for us, it would be toward the bottom of our list right now.