I've updated the OP with an IGN review for Tiger Woods and a videogamer review for GST.

I picked up Tiger Woods today. I was planning on getting Grand Slam, but neither it nor a standalone WM+ could be found.

Initial impressions are pretty good. The golf swing is very responsive and satisfying. The power of the gyroscope can be seen right from the start. I'm not a golf player, so I don't feel qualified to compare this to actual golf, but I can say that the interface is informative and intuitive, and the game is very friendly to golf noobs like myself.

Disc golf is very fun in multiplayer, but I found it to be a little too easy.

My only complaints right now is that I caught a hint of frame stutter, which is far from game-breaking in a game like this, and I've already had the game crash on me once (after the round, so no great loss).

It seems some reviews assume buttons are necessary to perform lobs and drops in Grand Slam Tennis, while some say they're not needed when using WM+ (including a quote which is in the official EA Sports site, so that's what I believe for now).

I got Grand Slam Tennis.

After the reviews I saw, must admit that I was really disappointed afetr 30 minutes of play. Thought the controls sucked (with or without Nunchuk) which really makes or breaks the game.

But then I realised that I was mainly flicking my wrist at the last moment and playing this like tennis on Wii Sports. Big mistake...

You really have to get into this game and accept that you will have to move more to get a shot off. For a forehand, set your feet right, take the racket back in advance of the shot and then let it fly. Same with backhand of course. Playing it this way makes you pull off the shots you want (I am still having trouble hitting shots down the line but have only played an hour).

All in all, the potential looks big in this one. Learning curve is much bigger than on Wii Sports so up to the player to take the time and perfect himself at this. I know I'll try...

Updated OP with a Tiger Woods score from X-play.

Sounds like the proper use of WM+ in these games has a fairly steep learning curve, especially in the case of Grand Slam Tennis. It seems like those who took the trouble to push past the initial difficulty (and maybe learn how to play with a nunchuk) are having a good time, though.

I know my first 18 holes of non-disc golf in Tiger Woods were terrible, but much of that was due to my near-total ignorance of golf. I got par or lower on 15 of my next 18 holes. Going from triple bogeys to birdies was very satisfying, and I look forward to improving my golf skills and maybe turning up the difficulty settings.

I picked up Grand Slam Tennis plus a Wii MotionPlus today and was confuzzled after my first match.. I really thought my MotionPlus wasn't working but it turns out I wasn't doing it right. You have to literaly move your entire body and swing your arm back and all the way through or you aren't going to get what you want.

Once you set into it though it feels very satisfying :)

GST does have a few issues but I hope I can work through them

I started on my first tourney at Bethpage Black (which for non-golf fans is notoriously one of the hardest courses in golf, especially for a public course), and eagled my first hole with an amazing chip in.  At that point I was like alright, im going to kick this game's ass, but then of course I hit hazard after hazard after hazard, and ended up 10 over par.  I am on the advanced swing mode, but I like it that way--I just definitley need some practice. 

Everyone should try the tournemant challenge mode, where you can relive certain moments from golf history--its a fun and quick way to build up stats and get money for your player with out playing in tournaments.

Just found this review in golf weekly.  It doesnt have a numerical score but is also very glowing:

"This year, gamers are faced with near-perfect 1:1 swing motion controls that at first will make most weekend hackers wonder why they are playing a golf video game that seems more difficult than real golf, at least on Advanced Swing mode. (Easy options are available for the kids and grandparents.)

In the game’s first four versions [for wii], it seemed more difficult to hit a draw or fade than hit it straight down the fairway. This year, if you don’t pay attention to – Pardon me as I jump into Unofficial Digital Hank Haney Mode – keeping your WiiMote flat and on the same line from backswing through impact, you’re going to end up throwing your WiiMote straight into the garbage. (Or lake, depending if your window is open and you live next to a lake.)"

http://www.golfweek.com/story/tiger-woods-video-game-review-2010

I can't wait to play against the Pros scores at Bethpage next week for the US open...

Hmm, after reading that, I don't think I'll ever set the swing mode to advanced ever. :P

From what I've heard you have to press buttons in Grand Slam Tennis to do certain shots but in Vitua Tennis you just do it like in real life.

If that's true then getting Virtua Tennis should be a no-brainer, right?

According to a quote from Nintendo Power (which is actually posted at the official site of Grand Slam Tennis) those buttons are optional.

http://tennis.easports.com/onCourt.action

Virtua Tennis also seems to be a bit more timing based than GST (i.e. more similar to the tennis in Wii Sports), while GST seems to take the direction of your swing. This is not confirmed though, just what some people have said.