The Bugera 333XL is a creation of Behringer corporation in the late 2000's to cash in on the desire for decent Tube Amplifiers at an accessible cost. The original lineup consisted mostly of copies of Peavey's most popular models such as the 5150/6505, the JSX (this one, the 333XL), and the XXX (333). These amplifiers were designed to fit into the lower-mid priced price bracket.
These amps started to ship in late 2007 and within 5 or so months, the issues with these amps started to come to light.
I bought my 333XL in this 5 month period in March of 2008, for just shy of $1000 w/ Bugera 4X12 cabinet. The main draw was that the head itself had 3 channels, decent reverb, a noise gate, had amazing tone (especially considering the price), and was exactly what I wanted for cheaper - as I was not ready to fork $3000+ for a Marshall TSL JCM2000 setup.
However, problems became apparent quickly. The main problems with these amps were....
The high power input transformer that supplies power to the tubes is connected via a nylon molex connector not up to the job of supplying such a voltage for the duration of many gigs and rehearsals. What happened was the Molex connector gets hot from shoving 120 Watts of 120VAC 60 Hz current into a quartet of EL34s (or 6L6's) and a quartet of 12AX7's, eventually reaching the nylon melting point, severing the connector from it's pins, cutting power to all tubes, and creating the problem where you turn on the amp, the tubes don't light up, you get no sound. This was resolved by me desoldering the original pin connector and then soldering lengths of wire down the traces on the other side of the board to make sure the solder could not get hot enough to cut-connection to the tubes.
The next problem is footswitches, especially now. The FSB104B footswitch does NOT have a modular cable. The cable is a proprietary mini-Din 5 pin connector with a L-shaped key so it only fits the right way. The cable is not up to the task for gigging for over 2 years and can break. Since it's not removable from the footswitch, it the cable is bad, you either have to replace the whole pedal, or go through a specialty electronics shop to buy the proper connector, then buy your own 5-6-wire cable to cobble your own setup. Once I could no longer replace these pedals - as Bugera I spose' expects us all to go throw $500+ down on a new Infineum model of this amp - I took matters into my own hands, and rewired it for D-SUB 9 pin Serial port connectors and use Serial port extension cables - so now I can go 31' away from the amp live with the footswitch, or scale it down for smaller stages, reducing tripping hazards - now THAT is a solution.
The input jacks can break under frequent use. When I first bought this amp - I was playing 3-5 shows a week with an original rock band and relied on this amplifier to work every night. That meant a LOT of cable installation and removal. Eventually the plastic anchors that hold the connectors to the chassis broke off, and I had to replace them. Ultimatley, my other main tonal Behringer product - a V-Amp Pro I bought in 2004, at 11 years old, blew up, and so I had some OEM replacement parts to cannibalize from that.
Since then, the amp has not been any trouble thankfully. I'm looking at buying up one or two more dead 333XL's to fix up as backups.
That said, the sound it makes makes all this trouble worth it. Some amps just have a "magic" about them, and this amp has some kind of sonic magic to it.
Cleans have very high headroom - I have put this thing on 12 before, and it does NOT break up even with a set of EMG actives pounding the shit out of the preamp. Very Fendery, even with EL34s. Bright top end sparkle. I think the Tone Stack was designed to appeal to those of us who like Fender Twin Reverb-like cleans.
The Crunch channel is classic Marshall. Nice midrange and upper mid spike, with a bit of a lay-back on the lows. With the XL switch engaged it gives a nice wider bass boost to things giving a slight Van-Haleny effect to the down. It can get pretty distorted, most of the time I run this around 5.
The Lead Channel is much like Crunch, but with a lot more saturation. It does have a "slight" fizz to it if you manipulate the tone stack too much with the active EQ. I don't actually use this for a lead channel so much as to push the gain up on my single-coil guitars.
The biggest feature though to me - for leads - is the FX loop - which also works as a volume boost for solos. This is perfect for my style since when I play solos I don't like my tone to change at all, just get about 3 or so db louder so that I can be heard. This takes a load of work off the Soundman, and takes a load of worry off myself because how do you expect your average sound guy at a dive bar to know exactly when your guitar break is if this is the first time he's heard you.
Since addressing these issues, it's become a rather reliable amp and I've not needed a backup for over 2-3 years, including a period of about 2 years where I was gigging 3-5 shows a week again after all repairs. My ex-bandmates Egnater was more trouble than this amp.