i've had a surround for arround 8 months now and love it, I use it primarily for music with my zune pass and the sound is fantastic witht he sound enhancer app from HTC i can choose an EQ setting that is great for what i'm listening to. This is basically what HP beats is just with a red color to make it branded and stylish ha.
The speakers are useful with the kick stand to show buddies videos and also when on the go and really wanna hear a tune on the train or having a drink and just need to hear that tune, but they aren't the all inspiring they were meant to be. Louder and crisper than any other phone, but still a phone and has limits depending on the setting mostly. I personally enjoy sliding the speaker in and out while i walk places don't know why it just feels cool I guess.
Screen size is fine, i haven't had any problems with it at all and I type with two thumbs like a champ. The device is heavy and blocky compared to other phones, but HTC build quality makes it easy to hold in hand, but its a noticeable difference. I love the look of the HTC phones and the camera button is so distinguished I rarely miss a shot. It hasn't been till after about 7 months into using the phone that I have decided that a switch for myself to a smaller phone or thinner might be more beneficial.
I can't decide between using the original focus which i stopped using due to the stupid microsd slot kept resetting the device, or upgrading to the titan next weekend for black saturday.
Hope that helps, if you got any specific questions let me know.