I had a BH Lamdstar and it may have been a step down from the BH 505 but I had trouble in my area with ground balancing, cheap construction and a less than user friendly control. I may not have given the machine enough time. However I find the ML detectors to be much more user friendly in terms of the control panel and the build quality is much better. My soil shows to be a bit towards the hot side ( Xterra 705 will GB between 9 and 30 usually) and the Minelabs handle my soils very well. If you believe you want a First Texas product I would recommend a Teknetics or a Fisher.
Whatever you go with I would strongly suggest a machine with adjustable Ground Balance. No fixed GB machines no mater what, period. With the possible exception of a machine for your children then go with something not BH, maybe Tesoro. I see that some folks like their BH machines, but if you look around you will find that many who use Minelab, Garrett, Whites, Tek, Fisher or Detector Pro have had modern Bh machines and realized they do not cut the mustard. One who comes to mind is GoGoGopher.
Thing is in the BH forum you will find that guys like the machines. On every other manufactures forum you will find them poorly regarded except for some older models. I personally have nothing bad to say about any other mfgs other than weight.
I have used the BH Landstar, Whites Classic ID (Pro ?), and the Troy X5, besides what I currently own, and prefer my current machines. I like multiple tones or the X5 and Classic ID probably would have done better, well except for the discrimination layout.
Jeff