I've not used the 7" round format, but I've used the 5x8's on several vehicles, both Hella and Cibie. Either is a HUGE improvement over sealed beams and highly recommended.

Cibie had a more sharply defined beam pattern and the spread between high beam and low beam was more suited to lower vehicles like the MBZ, the Hellas have a larger beam spread(high beams point higher in relation to the low beams) and work better on my taller truck.

Proper aim is HUGELY important, far more so than with the random blob of light cast by sealed beams. Aimed incorrectly, these could look like a significant downgrade.

Avoid any LED/HID replacement bulbs, or anything with a blue coating. They're all crap, every single very last one of them.

Now, the dedicated LED sealed beam replacements can be a different story entirely, and this is the route I'd go if replacing my sealed beams now. By the time you do big wires and relays and fuses and such, the cost difference isn't as large. Once again, one must be extremely careful to get a good brand(JW Speaker, Truck Lite, etc) and not the garbage that is all over the internet. Candlepowerforums has an automotive section and those folks will steer your right.

__________________
617 swapped Toyota Pickup, 22-24 MPG, 50k miles on swap