I recently received the Fascinate to replace my Blackberry as the work phone. Here's my personal review after using the Fascinate for a couple months. I am currently on 2.1 and no rooting. Some of the issues I note below may be resolved with 2.2 or there may be workarounds which I may not be aware of. If so please comment
Pros
Call quality is generally pretty good
Attractive iPhone-esq styling
Big display area
Web browsing
Multimedia
Takes pretty good pictures and video for a phone
Cons
Lag. I thought the strength of the phone was supposed to be the latest processor, etc but I find that the phone is very laggy typing, opening applications, etc. I go to the task manager and kill any apps but this does not resolve the lag. There was a also a video posted of the Fascinate vs the Droid X and what I saw was that the Fascinate opened web pages faster. However, when I put my phone next to my co worker on his Droid X, his seemed to open the page slightly faster. But he is running 2.2 which is not available on the Fascinate yet.
In the contacts when you try scrolling through the contacts, the lag causes the scrolling to get "stuck" and as your finger is scrolling up when the lag clears up the finger motion causes the contacts list to scroll by too fast. Very annoying.
Typing, I still prefer and can type faster using the hard keys found on the blackberry so maybe this may be more subjective. Typing on the screen keyboard is very inconsistent and I find myself making alot of mistakes.
Some of the problem may be me trying to type on these screen keyboards but after some experimenting, I found that when I am typing, the phone seems to start lagging. So when I hit a key and my finger starts moving to the next key, there is often a lag, which for some reason causes the adjacent key to get inputted instead. I also type on the Iphone 3GS which I have as a personal phone and I still make mistakes but they are no where near the amount of typos on the Fascinate.
UPDATE, i have been playing with the Iphone more and found that the lag is not there like the fascinate and the typos are minimal compared to the Fascinate.
Cannot view html based emails on the default email client. Shows up as a bunch of links. Even my blackberry was able to show web based emails
Bluetooth. When it pairs with my bluetooth in the car, cannot use visual voice mail at all. Also, when it is paired, you cannot use any voice commands. The phone does not "hear" anything when it is paired and you cannot use any voice commands.
UPDATE, there was a recent update from Verizon/Samsung (not 2.2 but some type of update) which seems to have resolved the bluetooth issue
Copy/Paste, only seems to work in certain areas and for the most part is not an option.
No corporate directory lookup. Co workers running DroidX and Incredible all have this option.
Email attachments. Example, go into email and try and attach a pdf file that's on the sd card. No where to be found. But when you go into the "my files" application, the pdf file is there.
No external notification (led) of emails or msgs received.
Cannot password lock the phone.
Sometimes the orientation seems to get "stuck" and when you have it in landscape or portrait, the screen does not adjust back when you turn the screen. Have to fiddle with the phone to get it to adjust in the correct mode.
The "buttons" on the bottom (menu, home, back and search). I would expect these to stay lit up so I can see them while I am working on the phone. These are not real buttons so there is no tactile feel. Instead the lights turn off after a few seconds and if you are working in a dark area, you have to guess where the buttons are, for example, to go to the home page. These buttons should stay lit up when you are working on the phone or have that option.
Default web browser has no page forward option. I have since migrated to Dolphin browser.
For some reason, when I grab the phone I will often hit the volume buttons or the side lock/unlock buttons
Battery life. In my opinion the battery on the phone does not last very long. I cannot go all day without having to charge sometime during the day in the car. So for heavy users, this may be an issue.
UPDATE, there was a recent update from Verizon/Samsung which addressed the bluetooth issue above but then my corporate email would not work. Had to delete account and recreate it. Also, the phone seems more laggy now than ever as well as locking up. Simple tasks such as opening your email, phone, etc should not have a few seconds of lag at every click. It doesn't matter that the phone has one of the latest quickest processors if it cannot handle simple things like opening/closing applications or inputting keys without significant delays.
Again, I use this for work and my recommendation for business users, especially ones coming from blackberry, is to check out the Fascinate carefully and weigh what's important to you. If I had to do it again, I would not have gotten the Fascinate, at least for business purposes. Perhaps alot of this will be addressed in 2.2 update but from what I have read, people have been waiting a while now for this update. In my opinion, Samsung released a phone that was aesthetically appealing but functionally lacking.