As near as I can tell (by looking at the TRO) the Eagle uses a standard engine, so it is cheap and 'durable' for a 25 ton mech. And it does have jumpjets, and a main weapon with a 19 hex range which it can use with no heat problems. So its far from useless, though you get back to the classic light fighter problem, in that in order to keep from being hit, it has to take actions that make it very hard to hit back.
With TW rules, the 1 is probably the better bet. Granted TW improved both AMS and TAG, so both are better than they were in 1998, but as noted getting a mech with only 5 tons of armor into a position to call in huge artilery or LRM strikes would probably attract a lot more attention than keeping it at 19 hexes and offering a bit of support, so being able to shoot down the odd LRM will help that armor last just that much longer.
As for value, its cheaper both in cost and BV than the origonal Panther, and I'd sooner have an Eagle than an old Panther (which I do like in its day, mind you) so not half bad for that. Not a half bad way to get an ER LL on the field, if you ask me.