Welcome to FishLore and welcome back to the hobby.
Although Eheim filters have a very good reputation I looked at the specs for both listed filter and was surprised at the very low flow rates. So I personally wouldn’t be very excited about either of these filters for a 55 gallon tank.
Also I noticed that the Penn Plax Cascade 700 requires screwing and unscrewing the intake and return hoses from the canister housing to perform maintenance. I’m not sure if your limitations would allow for this or not. But I got a canister filter so I wouldn't have to mess around with filters. So as a personal choice I’d rule that filter out right away.
I run a Marineland C-220 in my 35 gallon tank which is actually rated for 55 gallon tanks and has a flow rate of 220
GPH. Which would get you at least 4 water changes an hour in your tank. Although I might also suggest that the C-360 might be more appropriate for a 55 gallon tank (6 cycles per hour).
I actually run two filters that gives me a total of 420 GPH so I’m cycling my tank 12 times an hour.
If you would like to have a look at the Marineland models you can see them here…
http://www.marinelandc-series.com/
No mater your choice in manufactures I would suggest that you look at a system that will cycle your water more often then either of two filters mentioned.