I’ve owned the XA30.5, INT-30A, XA30.8, INT-150, XA-25, and nearly all the First Watt amps at various times. The only amp I have ever recommended to anyone, with absolutely no reservations (well…unless you need a ridiculously massive amount of power, which most simply don’t), is the XA-25. AMAZING amplifier. I will never sell mine unless Nelson makes an even better version. It is a bit of an outlier in the line as it uses unique output devices. I can’t remember what they’re called, but they’re not the mosfets nor jfets which Nelson has used in various combinations over the years. Apparently these special output devices play a key role in this particular amp’s performance. As you know, the INT-25 is the XA-25, but with a simple preamp stage built in. I just can’t recommend the XA-25 highly enough, which makes the INT-25 an easy recommendation too. Definitely give it a try before you settle down with anything else.