I have been using ultrasonic plus point nozzle for a number of years now- had the AD, and still have the KL, which I use along with a big Monks (Omni). I think the combination is synergistic - and the results of using both methods - US and vacuum-- in combination are particularly evident with older/used records.
DIY US offers more flexibility than the "commercial" US machines meant for LPs- you can control heat, degas, power, and frequency as well as use different surfactants.
If you are going the DIY route, be mindful of the relationship between surface area, tank size and the power of the transducers-- there is a formula on page 5 of the long diyAudio thread that discusses this--where the author points out that 12 inch records act like a baffle and reduce cavitation effect.
I think the Elma is the way I’ll go when my KL gives up the ghost, though it (the KL) has been reliable, it suffers from some limitations. The transducers on all these things eventually burn out, which may make buying a cheap unit seem more sensible.
PS: Rush Paul’s seminal article (published here on the ’Gon and in Positive Feedback Online) which takes the collective wisdom from the long diyAudio thread and applies it, along with some of the tweaks, including an external pump and filter, is well worth reading, as is a similar piece Tim Ackerman wrote with a follow up (and published on my blog, TheVinylPress.com).