Started to consider to connect with another node for latency reasons, and
this node 73.252.200.173 gives me 40-50% better ping performances and as
I understand, the faster you can send/receive, the better hashing/mining performance, right?
...
The Ping Results from my network, to this node are better than 50ms which is what started to draw my attention.
As mentioned in p2pool.org's node scanner, its ping time is a simple HTTP request from your browser, not the ICMP ping that's used when you ping from your network using the ping command. You should follow the ICMP ping results, as that is usually a more reliable measure of latency than a browser's HTTP request.
Is this node good/bad/dead or worse?
Could I get a little help in considering this node, or another node to connect to?
...
I can't say for certain whether or not that node is good, bad, or dead. All I can say is that that node is active and open to the public, for now. If you choose to mine at that node, you would have to trust that node's operator to keep it running (and running well). This is why it is highly recommended to set backup P2Pool nodes in your miners' configuration when mining with P2Pool, so that if your primary pool goes down, your miners would failover to another P2Pool node without missing a beat.
Personally, I would not mine at that node.
If you decide to move away from p2pool.org's node, then I recommend OgNasty's
NastyPool node. Better yet, if you have the required computing resources and technical know-how,
set up your own P2Pool node — this frees you from having to trust a node operator.
to be more to the point, is this a node I should switch to?
That is up to you. I would not recommend it, though. I personally would not mine at that node.
Are there concerns about the Hash Rate & Efficiency being blank?
There are also ZERO users there
The hashrate and efficiency statistics are blank
because there are zero users there.
The pool rate looks interesting, right?
Pool rate: 2.63PH/s (19% DOA+orphan) Share difficulty: 712000
The pool rate is the total hashrate for P2Pool
as a whole, not for the node you're looking at.