Summary: I'm experienced with PHP web software. Combining plugins inevitably lead to the Blank Screen of Death. Search all over the internet for a solution. Try several solutions that do not work. Get dissuaded from asking for help by responses seen to similar problems. The Blank Screen is only be rectified by a complete reinstallation. Wash and repeat several times with different plugin combinations. Done with WordPress.
I am no expert and do not consider myself a developer or programmer. I simply consider myself experienced in setting up, breaking, and fixing PHP-driven websites.
I went through several separate installations of WordPress. WordPress requires a lot of plug-ins for many functions. Which is good, I like lean but extensible platforms. I tried WordPress and WordPress Mu. I also tried varying packages of plugins with both versions to achieve the functionality I desired. I wanted a community website with integrated forum and chat. There are a lot of plugin combinations that can achieve these ends.
The server my site is hosted on works perfectly fine for any of the required functions for WordPress (i.e. mod_rewrite) with other software packages and test code. Thus, I can be sure that my hosting environment is not the source of the woes.
The Blank Screen of Death is what killed my WordPress experience. With every thing else I've used or experimented with, there was always at least an error message. Not always an immediately helpful one (alas, PHP), but usually enough for me to trace the process or use the almighty power of web searching to rectify the issue or identify the conflicting bits. WordPress gave me a white screen. A blank white screen. Whose source code (view source, nice browser tool) was also completely blank. The problem could only be rectified by completely wiping the install and starting over.
I'm perfectly aware that plugins, in bad combination, can break any blog, forum, CMS, or similar software with ease. However, I have never experienced such common problems from any other software. The most common problem experienced in other software is that the plugin simply doesn't work or plainly has a conflict with another plugin. I'm also experienced enough to activate plugins one at a time, try different activation orders, and try different sets of plugins. My experience cannot be traced or pinpointed to any single plugin, type of plugin, number of plugins installed, or particular group of plugins.
The worst of it was the (often not entirely friendly) replies, and pointed lack of replies, to people experiencing similar issues that I saw on this site and other WordPress-focused communities. The chance of a friendly and earnestly helpful reply to my problems seemed close to nil.
I don't plan on ever using WordPress again unless problems like this are solved. If someone wants a staightforward blog, it serves the purpose well and I'd still recommend it for that purpose. If anyone wants to do anything requiring a lot of extensions and customization, I'd strongly discourage them. I'm going to be using another solution for my needs that has more stable plugin interaction and a more obviously friendly/helpful support community.
I'm sorry to be so negative, but that is my experience as someone who attempted to put this software to use and spent a lot of time searching for solutions. If WordPress lacked the utterly unhelpful blank screen issue and had better plugin interoperability, I wouldn't be posting this right now.