I have one of these amps, got it a few years ago and have found it to do the job nicely. It has the distinctive Marshall tone and is a great budget option over the more expensive tube models. I'll give you the good and the bad.

Good:
Nice tone, sounds from very quiet to very loud (the tube amps only sound good when cranked to ear bursting levels). Built in effects are not bad, you can get a nice lead tone and rhythm are very clear. It's loud enough to play with a drummer without having to go through a PA. The amp comes with a speaker simulator is very handy for recording at home if you want to keep noise to a minimum or don't have microphones etc.

The bad:
The fan in these models are known to give a loud audible hum - however it dies down after about a minute or so - no biggy. The Eminence speakers do not project low end power as well as the Celestiens in their tube counterparts.

This amp is best suitaed for metal (80's and early 90's tones) - the clean is ok but a little brittle - this can be very hard on the ears at high volumes. Personally, I love the Marshall tone for very fast shred passages off the neck pickups - especially for sweep picking, very nice distinctive rolling tones from string to string. If you have the cash though, check E-Bay for a Marshall TSL601 - it's the upper end 60 watt tube model with great tone and a lot of tone shaping options. You may be able to get one second hand for not much more.

Re the DFX, don't get the head and cab version, the 'all in one' amp sounds better, is more compact and gets better reviews overall.