At the outset I'd like to remove any doubt as to how I feel about this phone: the T616 is absolutely the best phone currently available (in the U.S.). There are only three phones that even come close to its feature set: its predecessor, the SE T68i, the SE P800, and the Nokia 3650, which is really no match as it has to be one of the ugliest phones I've ever seen, not to mention that it's about twice the size of the T616.
It should be noted that the only difference between the T616 and the T610 is that the T610< operates at 900MHz, while the T616 uses the 850MHz band (both are triple-band GSM and can also use the 1800/1900MHz frequencies). I make the point only to clarify that they are exactly the same phone, save their antennas.
The biggest deal for me, coming from a Sony Ericsson T68i, was that SE fixed the damn calendar application so that it now correctly syncs with Apple's iSync utility. I would not have bought the phone if this had not been fixed. Previously, with the T68i, all calendar entries would get shifted by one hour. This meant that after you did your first full sync, you would get two entries for every single appointment — an hour apart. Even though all is fixed now, I was still required to change the "Daylight Savings" setting to "1h Summertime." I had to spend some time playing with these settings before everything was syncing correctly, but I haven't had to touch it since I got it working. The PDA is dead; long live the smartphone (this isn't really a smartphone, but... :).
I've had zero trouble using Bluetooth to connect the phone to my PowerBook. Apple's Bluetooth support is quite remarkable. On top of syncing all of my information through Bluetooth, I also use it for Caller-ID and SMS sending/receiving through the computer. I simply open up the Address Book and click the Bluetooth icon. If a call comes in, I get a pop-up window on my computer that tells me who it is (I don't have to take the phone out of my pocket to see who is calling). Similarly, if I'm sent a text message, the message will show up in a little window on my computer. If I want to send a text message to someone, I can simply open up the Address Book, right-click on a contact's mobile phone number, and choose "send message." When I send the message it is sent to my phone over Bluetooth and then from my phone to the contact. Very neat. All of this says nothing of the Clicker software.
The menuing system is faster and much more responsive than that of the T68i. There's always a trade-off though — they removed the joystick counter from the secret menu. :\
The T616 also adds a recurring alarm. You can give it a time and then select the day(s) of the week that you want the alarm to go off — perfect for me as I have to get up at the same time M-F. If, for whatever reason, you need to change the time of a particular day, you can do this without disturbing the recurring alarm. A great feature all around.
The battery life is very impressive, especially when you consider that it's powering a fairly bright 16-bit color screen. I certainly can't complain about its modest power consumption.
As is always the case, I have a few gripes. The first, and the one I'm most upset about, is the loudness of the speaker (during phone calls) — it's rather low, even on the highest setting. I've read that this can be fixed with a firmware upgrade, but I've yet to find someone in the Bay Area who can do this (granted, I haven't spent any time trying to find someone as I don't have said time :P). To add to that gripe, I'm also pissed that there is no speakerphone — this is perfectly doable given the loundess of the ringtones. Perhaps this too will be added in a future firmware update. I know this was one the big complaints with the T68i, so it surprises me that it wasn't added to the T616, especially when the Nokia 7210, Nokia 7250 (both are tiny 'candybar' phones), and Sony Ericsson's own P800 have this feature. No excuse.
Another major shortcoming is the limited amount of memory that comes with the phone. You are only alloted 2MB (though there is a "13-second trick" which can bump it up to 2.5MB). This might seem like a lot to some, but as soon as you start taking a few pictures, receiving (and saving) SMS messages, downloading J2ME/Mophun games, and playing with some themes, the memory dissipates quickly. I can't say that I've run out of memory yet, but I know that some people really have to juggle to keep what they want on the phone.
As I've said in the past, I really don't care about having a camera on my phone, but it just so happens that the best phones these days come with them (this is my third camera phone). If they had left this feature out, I would have still bought the phone — in fact, I would have liked the phone even more (it would have been cheaper and would have had one less thing that could break). Camera phones are nothing but a novelty to me; until they reach 3MP+ I just don't care. Given all of that, I can't really comment too much on this phone's camera. It takes decent pictures (though the max resolution is 288x352), has a "night" mode, and offers three effects — B&W, negative, and sepia. It also has a self-timer. For the vanity in all of us, it comes with a small mirror (that plugs a hole in the back of the phone; defaulty plugged with a rubber stop) so that you can take pictures of yourself. If I want to send a picture to the computer, I simply choose, "send | via Bluetooth." Done.
Lastly, I'd like to talk about the phone's design. I think one would be hard-pressed to say that the phone isn't easy on the eyes. It's so simple and yet so perfect. Less is definitely more. The indented sides provide a great grip on the phone and also allow you to set it down horizontally on a surface to take a picture. I put up some hi-res photos (from SE's site) — if that isn't great design, I'm not sure what is.