The Party Poker software is very good, with a number of upgrades they made in 2003, early 2004, October 2005 and February 2006. I am not a big fan of the graphics they were just too ordinary, but from a practical standpoint the playability is good.
With its amazing growth, Party Poker has added servers and increased bandwidth in order to secure full relability at 100,000 simultaneous players. However, a few players have complained about delays and disconnections at certain tournaments. Overall, Party Poker is much more reliable nowadays, in line with or better than most of the competition.
Four simultaneous tables per player are allowed. Unfortunately, the view flop percentages are not presented, neither are hands per hour rate. They do give you the option to see the last 20 pot sizes. This is something Party Poker will have to change on their next upgrade.
The options Party Poker gives you for your personal playing records are somewhat simplistic, but it works well. Player notes function is included as well as instant hand histories. In October 2005 a new platform was lauched which removed the Party Poker players from the skin sites and now lets them play at their own private tables. Also new features like black jack, deal-making, and side bets are available while playing at a poker table.
A nice feature of party Poker is the very smooth table resizing option. You have the option to auto resize all open tables meaning will resize and spread out evenly on the screen by the click of your finger. Resizing does not work for Omaha and 7-Card Stud games.
In sum, the improvement Party Poker has made over the last few years has greatly improved the sites playability and the amount of people who can play at one time without problems.