I'm probably more like 80% table and 20% hand-held. Looking strictly at hand-held, much of that 20% is plunge routing, the rest could be done fixed base or plunge. With the Bosch 1617 EVSPK, the fixed base is designed for table use, which leaves the more versatile plunge base for hand-held work. Many routers recommend the plunge base in the table, which means removing the table-mounted base if one needed a plunge router for a hand-held operation. If i only had one router for hand-held work, i'd much prefer a plunge base.
As for table mounted...Another nice feature of the 1617 is that the depth adjustment is all vertical, no rotating the machine to set the depth. This allows the switch, depth adjustment and base latch to be in the same position all the time. Not sure on the Hitachi plunge base, but if i recall correctly in the fixed base it's a motor twist to set depth?
Everything i did with a router this weekend was hand-held--and i needed the plunge base most of the time. Other people may feel differently, but I do like my 1617!!