No, they aren't.
TS% is an amalgamation of three shooting percentages mashed up into one number + a 1.44 point given for FT's. It's bullshit because it can show someone having better game than they actually did because they may happen to be a great FT shooter. That will always bump the total percentage up, even if they shot terrible from the field. It's a weak stat.
PER is just some number John Hollinger pulled out of his as and then admittedly reworked so Michael Jordan would always come out on top.
Read this about PER
Problems With PER
PER largely measures offensive performance. Hollinger freely admits that two of the defensive statistics it incorporates -- blocks and steals -- can produce a distorted picture of a player's value and that PER is not a reliable measure of a player's defensive acumen. For example, Bruce Bowen, widely regarded as one of the best defenders in the NBA (at least through the 2006-07 season), has routinely posted single-digit PERs.
"Bear in mind that this rating is not the final, once-and-for-all answer for a player's accomplishments during the season. This is especially true for players such as Bruce Bowen and Trenton Hassell who are defensive specialists but don't get many blocks or steals."
The formula of PER requires adding values with different units which is prohibited by unit analysis. For example, the formula adds assists to rebounds with no conversion factor.
In addition, some have argued that PER gives undue weight to a player's contribution in limited minutes, or against a team's second unit, and it undervalues players who have enough diversity in their game to play starter's minutes.
Lastly, PER rewards inefficient shooting. To quote Dave Berri, the author of The Wages of Wins:
"Hollinger argues that each two point field goal made is worth about 1.65 points. A three point field goal made is worth 2.65 points. A missed field goal, though, costs a team 0.72 points. Given these values, with a bit of math we can show that a player will break even on his two point field goal attempts if he hits on 30.4% of these shots. On three pointers the break-even point is 21.4%. If a player exceeds these thresholds, and virtually every NBA player does so with respect to two-point shots, the more he shoots the higher his value in PERs. So a player can be an inefficient scorer and simply inflate his value by taking a large number of shots."
Problems with PER Projections
The projections are built by looking at comparable players at the same age and how their stats changed in the following season. For players in most age brackets, this is extremely reliable, but there have been so few players to turn pro out of high school in the past two decades that there is a very small sample to work with. While some players who have come out of high school have shown a lot of promise in their future years, many have floundered and never quite reached their full potential.
In other words, Bullshit stat is Bullshit.
Also, FG%, 3-point%, FT% are all you need. Why? Simple, when you look at stats like TS%, you get one number, but it doesn't tell you shit because it doesn't break down ANYTHING that happened on the floor. So what will you ALWAYS wind up having to do?
That's it, you guessed it, go right back to looking at the RAW stats. Then, you can see, he shot this way from the floor, this way from 3 and this way from the FT line. Then you'll know EXACTLY what he did and by this, you can even count up how many points he from and from where, that's something you can't get from TS%, which is what makes it a bullshit stat and not advanced at all. It's a worse stat due to it's ease of manipulation.
But yeah, go ahead and go with those BS stats that really don't tell you anything that happened on the floor.
One more thing about PER, look at how it is calculated.
When have to do all of THIS for a basketball stat, you need to stop.
http://en.wikipedia.org/wiki/Player_efficiency_rating
