I wouldn't base your decision solely on those metrics. Both schools have strong networks but are very different in other ways. 

Cornell's LA dept is in their agriculture school. It's separate from the other design disciplines. It's a very strong program for horticulture and ecology. 

Penn is a leader in landscape urbanism and has consistently been pushing the boundaries of what the discipline is capable of. McHarg connected design and ecology. Spirn and Hunt reshaped how we view cities and gardens. Corner brought imagination back into the discipline. Weller is traversing across scales from the site to the mega-regional. If you want your ontological assumptions about nature and culture challenged on a daily basis, this is your school. 

Also Philadelphia is very different than Ithaca. 

Good luck!

look at the staff of firms you want to work at and see if one weighs more than the other; also look at who you want to study under (where your interests are in relation to the faculty).  another consideration is the student body, schools tend to attract/foster a personality type - it's important that you fit in (collaborative, competitive, etc).
 

To expand on the comments of reddishegret and 3tk, what are you looking for in an LA degree, besides alumni connections and networks? IMHO that's a lazy approach and will not serve your education in the long run. Not mention- just ask the question of their alumni and placement offices, instead of asking a bunch of people who are only partially informed. Do you want an MLa/March? MLa/re? MLa/Mrp? (Advice, don't use the overly vague phrase urban design because they will both have urban studios, it's HOW you want to address urban design that matters).

Assume that the core requirements are the same-

-Studios. Evaluate the work that is available for viewing.

-A demonstration of site grading and topography

-Plant identification/ecology

A-Site construction and assemblies

Then look at the subtle differences offered in the history/theory requirements. 

Followed by looking at the elective list. Note that these courses may not always be offered, but it gives you a sense of what the faculty is working on.

Then look at facilities. You may need to do a little digging to find out what each program actually has access to, and how they use them. 

Good luck!

xtang,

One more consideration. If you are already receiving a bachelors degree from one of the institutions, you may benefit from applying to the other mla program(s). As an example, there are programs that will not graduates of their BLA/BSLA programs into their MLA programs.

As an example, if you happen to be completing your BSLA at Cornell you likely be encouraged to go to another program.