I've made a comparison table (in Google Docs) (light HTML link) for converting between netstat and ss arguments. It's too big to include and update it here.

The short version of difference between short arguments is:

Arguments that require attention: r N i g M W T v C F c A U 2 f

Arguments that are safe to leave as is: h V l a n Z s p e o 4 6 x t u S w

I stumbled across this post while researching netstat -> ss conversion. Outstanding table but I wanted to point out one thing in particular... the man page description for the netstat -s command option states, "Display summary statistics for each protocol". ss -s option in the man page states, "Print summary statistics. This option does not parse socket lists obtaining summary from various sources. It is useful when amount of sockets is so huge that parsing /proc/net/tcp is painful." These two command options return EXTIRELY different information.

For example:

$ ss -s
Total: 1365 (kernel 0)
TCP:   276 (estab 163, closed 14, orphaned 0, synrecv 0, timewait 1/0), ports 0

Transport Total     IP        IPv6
*         0         -         -
RAW       1         1         0
UDP       24        17        7
TCP       262       246       16
INET      287       264       23
FRAG      0         0         0

as opposed to the netstat -s command output (truncated):

$ netstat -s | head -n15
Ip:
    2043673568 total packets received
    0 forwarded
    0 incoming packets discarded
    1997519606 incoming packets delivered
    1359233819 requests sent out
    53 dropped because of missing route
    22 reassemblies required
    11 packets reassembled ok
Icmp:
    38023 ICMP messages received
    7619 input ICMP message failed.
    ICMP input histogram:
        destination unreachable: 23947
        timeout in transit: 129

I don't know if the upstream developers of ss intend on expanding the available output from the command, but near as I can tell... ss doesn't offer anything equivalent to the netstat -s statistics.

/ SenseiC bows out

I use "show sockets":

sudo ss -ltpn

This command also shows the associated processes:

State         Recv-Q         Send-Q                    Local Address:Port                   Peer Address:Port
LISTEN        0              128                             0.0.0.0:111                         0.0.0.0:*             users:(("rpcbind",pid=844,fd=8))
LISTEN        0              100                             0.0.0.0:8080                        0.0.0.0:*             users:(("java",pid=1554,fd=60))
LISTEN        0              128                       127.0.0.53%lo:53                          0.0.0.0:*             users:(("systemd-resolve",pid=1048,fd=13))
LISTEN        0              128                             0.0.0.0:22                          0.0.0.0:*             users:(("sshd",pid=1891,fd=3))
LISTEN        0              1                             127.0.0.1:8005                        0.0.0.0:*             users:(("java",pid=1554,fd=76))

Swap -t with -u for UDP instead of TCP.

In the beginning I always used -ltpan, but sometimes that shows a bit much.

ss -h (help on Ubuntu 18.04):

Usage: ss [ OPTIONS ]
       ss [ OPTIONS ] [ FILTER ]
   -h, --help          this message
   -V, --version       output version information
   -n, --numeric       don't resolve service names
   -r, --resolve       resolve host names
   -a, --all           display all sockets
   -l, --listening     display listening sockets
   -o, --options       show timer information
   -e, --extended      show detailed socket information
   -m, --memory        show socket memory usage
   -p, --processes     show process using socket
   -i, --info          show internal TCP information
   -s, --summary       show socket usage summary
   -b, --bpf           show bpf filter socket information
   -E, --events        continually display sockets as they are destroyed
   -Z, --context       display process SELinux security contexts
   -z, --contexts      display process and socket SELinux security contexts
   -N, --net           switch to the specified network namespace name

   -4, --ipv4          display only IP version 4 sockets
   -6, --ipv6          display only IP version 6 sockets
   -0, --packet        display PACKET sockets
   -t, --tcp           display only TCP sockets
   -S, --sctp          display only SCTP sockets
   -u, --udp           display only UDP sockets
   -d, --dccp          display only DCCP sockets
   -w, --raw           display only RAW sockets
   -x, --unix          display only Unix domain sockets
       --vsock         display only vsock sockets
   -f, --family=FAMILY display sockets of type FAMILY
       FAMILY := {inet|inet6|link|unix|netlink|vsock|help}

   -K, --kill          forcibly close sockets, display what was closed
   -H, --no-header     Suppress header line

   -A, --query=QUERY, --socket=QUERY
       QUERY := {all|inet|tcp|udp|raw|unix|unix_dgram|unix_stream|unix_seqpacket|packet|netlink|vsock_stream|vsock_dgram}[,QUERY]

   -D, --diag=FILE     Dump raw information about TCP sockets to FILE
   -F, --filter=FILE   read filter information from FILE
       FILTER := [ state STATE-FILTER ] [ EXPRESSION ]
       STATE-FILTER := {all|connected|synchronized|bucket|big|TCP-STATES}
         TCP-STATES := {established|syn-sent|syn-recv|fin-wait-{1,2}|time-wait|closed|close-wait|last-ack|listening|closing}
          connected := {established|syn-sent|syn-recv|fin-wait-{1,2}|time-wait|close-wait|last-ack|closing}
       synchronized := {established|syn-recv|fin-wait-{1,2}|time-wait|close-wait|last-ack|closing}
             bucket := {syn-recv|time-wait}
                big := {established|syn-sent|fin-wait-{1,2}|closed|close-wait|last-ack|listening|closing}