I went out to try some cabs the other day with my stuff.
Hartke transporter 410
My SWR WM410T was louder and sounded better to me.
Your best bet is to go out and try some. Most " pro quality" cabs are less efficient than weekend warrior cabs and will need more power (to achieve the same loudness) than the E300 can dish out. But that is also related to how loud you need to be.
Only you can answer this question. Find a cheap 8 ohm cab you like the sound of and buy two!