I used to do tech writing and manuals for datacomm products, especially for products I helped develop.
Those two little questions aren't so little!
1: Consistency. They key to consistency is two things. First, the obvious is consistent placement of the fixture. The second is really the fixture itself. I think for example, the X-Move LED Spot first generation was very inconsistent with how it would move around. Many people complained it would drift. They had to power cycle the light to get it to properly return to zero. This isn't practical.
Now, not to bash any ADJ product or praise any Chauvet product needlessly, but I have a pair of Chauvet Q-Spot 150's, which I've had for several years now, and using them for near 3 years with MyDMX, the results have been very consistent. In the big show I am working on, te lights hit exactly where I want them to each and every single time. Fixtures with X and Y channels, plusX and Y fine channels have 16-bit movement, and hence tend to use better motors. The added price reflects this more expensive technology. As per typical, you get what you pay for.
Despite my good results with these lights, which haven't given me any issues, I am looking to replace them, or at least get more movers.
Question 2 regarding optimization. Optimization really comes down to how much work you need to do with your computer. In my case, my 17" MacBook Pro has to do quite a bit of work besides MyDMX. My suite of software includes MS Office, Photoshop CS3 Extended, Pagemaker, Sonar Home Studio, Nero 7, Sony Vegas Pro 9, ProTools M-Powered 74.csXX and many other applications besides MyDMX. With the kind of money I put into this computer($3400+ at purchase with screen and CPU upgrades, then a later RAM upgrade I did), we're talking close to $3600 for this laptop. No way it's just doing one thing.
For any computer, especially going on the internet, a few things should be done. The first is to use a broadband router to prevent direct attacks to the operating system by dirtbag spammers. The second is anti-virus software, which I've been recommending Norton Anti-Virus for at least 15 years. For spyware protection, I recommend Spybot Search & Destroy, which is free. The only downside is you must manually run the updater and search, but do that once a week. Tihs three-level approach will prevent MOST problems.
Now, as far as optimization, again, it really depends on what you need to do or can afford to do. Since you're most likely not going to waste a laptop just for MyDMX, my suggestions are as follows:
When using MyDMX, I recommend that you disable your WIFI and network adaptor. The computer won't do queries for DHCP and sniffing for networks. This is more critical for WIFI as unline the wired network, WIFI will continously try to find a network to connect to. One of the gripes about XP and later is that sometimes you just want it to fail, and WIFI takes more to fail. WIFI tends to be more of a resource hog sa well.
Other things to turn off is Apple Mobile Services and anything related to Ipod and Itunes, I have an iPhone, but I use my MacBook Pro as a Mac when dealing wiht my iPhone. When I use myDMX, I am booting using BootCamp and coming up as a PC.
Look at your system tray and look at other things that you don't absolutely have to have.
Type MSCONFIG in your RUN box and disable other things you don't need.
If time permits, I like to redo my entire computer(all of them except for servers) at least once a year. This just genreally cleans out any crap that has accumulated and helps keep things optimized as well. Then, only install what you can't live without.
Overall, I have found that disabling WIFI to be the biggest optimization. If you use the 3D Visualizer, especailly live, the faster CPU"s, better graphics cards and more RAM re definate must-haves.