I haven't heard the SRM-007t vs a T1, but I am not all that convinced that the 007 is worth the money. The reason is that the 007 uses the same antiquated output design as the T1 - specifically, it uses plate resistor loads. The problem with plate resistors is that, per Ohm's law, V = IR. Since the plate resistor is lower impedance than the headphone, this means that the majority of the signal current generated by the output tubes is wasted, burned up as heat in the plate resistor. The lower the value of the plate resistor, the more signal current gets burned up. Not only is this inefficient, but it also increases distortion, due to the increased amount of current variation needed to drive the headphones and plate resistor. The plate resistor values are 66 kilohm in the T1 versus 47 kilohms in the 007. Granted, the 007 has double the number of output tubes, but this only buys a 40% increase in standing plate current. It should be remembered that Stax did originally recommend the T1 to drive their Omega headphones, although they did later introduce the T2 for that purpose, and the Omega is considered more difficult to drive than any Lambda headphone.
However, a better technical solution to my mind than buying a 007 is the constant current modification to the T1 (or 006). This effectively eliminates the current wastage of the plate resistor, which more than doubles the amount of signal current available to drive the headphones. At the same time, the decreased amount of signal current needed decreases distortion. Also, the parts cost of modifying a T1 is around $100, so the overall cost should be significantly less than the cost of a 007, even if you pay somebody to do the mod for you.