F-Machine Tremblr

The tremblr is a bit cheaper, and has standardized sized dicktubes. I think it just uses a piston style plunger for air pressure. I believe you can use the business end on either device, but the only mixy matchy you would want is a venus tube on an fmachine. I would go with the f machine, for the slightly lower price, and the selection of standard tubes to use on guys other than myself.