I like Tachyon Beam. It allows me to run a torpedo-heavy science vessel without sacrificing all my shield firepower. It isn't a replacement for having ANY energy weapons, but it's a good supplement if you have fewer than normal. I use it alongside a dual beam bank, and fill the rest of my foreward arc up with torpedos.
I love Tachyon Beam. I make sure I have a few beam weapons and throw this up as well. Then throw torpedoes at them when the shields go down briefly. Wham ... lots of health loss Along with Tractor Beam to hold it in place and Tractor Beam Repulser to keep it away and of course the excellent Science Team. I love being a science officer on a science ship And those are just the skills my First Officer Lorin has
I have been a fan of it since the start, because as you said, looked very interesting. It loses a bit of power as you level, but I still find it usefull.
Not sure it stops shield regen, but it can be used on someone that used rsp and take it's shields down. I actually killed a few ppl like that on pvp, when they engage rsp shields are usually not good, so I stop firing, boost aux to max (I change my power settings during combat all the time) and use it, just followed but high yield torps, and that usually does the trick, if it's hull was damaged enough.
If I read the tooltip correctly it sends a pulse each 0.4 second during 3.6, for a total of 9 pulses. With my aux max(about 115) I get 305 a pulse on my Tachyon III, so that's a total of alboutt 2.7k for all facings. Unless I'm wrong about the number of pulses, it does a good deal of drain.
Edit - Major problem for me is that is shares cooldowns with Sub beam, otherwise I would use it more.